This document discusses key components of research articles and the research process. It defines sections like the abstract, introduction, methods, results, discussion and references. It also explains important research concepts such as independent and dependent variables, limitations, and the difference between qualitative and quantitative research. The overall summary is that this document provides guidance on the structure and methodology of research articles and studies.

1. Created by:
Allison Childress MS, RDN, CSSD, LD

2. http://www.youtube.com/watch?v=fh
LZ2I2MaeQ

3. 1. Title
2. Abstract
3. Introduction
4. Methods
5. Results
6. Discussion
7. References

4. Abstract
• A brief summary of the entire article in
approximately 120 words
• Contains a concise summary of the following:
(a) the article's problem under investigation or the
hypothesis
(b) pertinent information on the participants
(c) brief review of methodology
(d) statistical analyses
(e) results of the study
(f) implications of the study.

5. Introduction
• Body of the article
• Begins with a broad statement of the problem
being investigated then narrows to the
specific hypothesis (es)
• May include the review of literature (ROL) or
ROL may have its own section

6. Methods
• Provides a detailed description of how the
study was conducted
• No conclusions drawn here
Results
• Statistical reporting of data
• Describes what was found statistically from
the data
• Tables and figures

7. Discussion
• Reviews, interprets, and evaluates the results
of the study
• Non-technical language, no statistics
• Weaknesses should be reviewed
• Direction or future research
• Opposite of introduction
References
• Alphabetical order
• Correct format

9.  Advil
• “Nothing is proven more effective or
longer lasting than Advil.”
 Oral-B Toothbrush
• “You can buy a fancier toothbrush. But
you can’t buy a more effective one.”
 Duracell Battery
• “No other battery lasts longer.”
 Revlon Skin Cream
• “In just one week, fine dry lines and
wrinkles are reduced by over 38%.”

10.  The pursuit of
knowledge and its
dissemination is a
unique
characteristic of a
“profession”
 Research is the
basis for
advancing the
body of
knowledge of a
profession

11.  Not really a universal definition
• A structured way of answering questions,
a systematic method of inquiry
• Research is nothing more or less than
finding answers to a question in a logical,
orderly, and systematic fashion
 Two key components
• Systematic in nature
• Focuses on a question of interest
 Inductive and Deductive
Reasoning

12. Uses logic that moves from
general to specific
Model for review of literature
enables the researcher to organize and
synthesize available information,
theorize about the problem, and
deduce hypotheses to be tested by the
research

13. Lit Review:
• What is physical activity
• How can it effect human physiology
• What is Parkinson’s disease?
• Current treatment options for PD
• Physical activity and PD patients

14. Uses logic that moves from the
specific to general
Fundamental principle of scientific
method
• based upon observations of a small
group, generalizations are made to a
larger population

15. A way of solving problems and
acquiring knowledge that involves
both deductive and inductive
reasoning in a systematic approach to
obtaining information

16. Question Identified
Hypothesis Formed
Research Plan
Data Collected
Results Analyzed
Conclusions
New Questions
Arise

17. Through scientific inquiry (research),
facts are discovered
• The interpretation or explanation of these
facts is the basis for theory, which is a belief
about how things relate to each other
• Theory is not law, but could become law
through additional research and
experimentation
• A theory establishes a cause and effect
relationship between variables for the
purpose of explaining and predicting
phenomena (Best & Kahn, 1998)

18. Several research classifications have
been proposed
• Basic vs. Applied
• Quantitative vs. Qualitative
• Experimental vs. Non-experimental
None of the various research
categories are mutually exclusive

19.  Purpose is to discover new or
fundamental knowledge
 Practical application is NOT a goal
• Salmonella outbreak in cantaloupe
• Link between lack of physical activity & depression
 Because there is no intervention or solution to depression we are
just trying to discover a link
 Usually in highly controlled
laboratory settings

20. Purpose is to find answers to
practical problems
Diet protocol for soccer celiac disease
Recommendations for patients with diabetes
Creating a pesticide to reduce the outbreak of
salmonella in foods
Creating an exercise intervention for patients
diagnosed with severe depression
Practical in nature
Inferences or generalizations are
made to the intended population

21.  Positivist paradigm
• Scientific knowledge can reveal the
truth
 Traditional model of research
 Hypothesis directed
 Based on firsthand evidence
• Observed or experimental
 Measured with numbers
 Analyzed statistically
 Examples:
• Decrease in BF% after semester long Zumba course
• Increase in STAR scores with mandated PE courses

22. Naturalistic paradigm
multiple interpretations of reality and the goal
of researchers working within this perspective
is to understand how individuals construct
their own reality within their social context
Reliance on qualitative, non-
numerical data
Variety of methodologies
in depth interviews
direct observation
Focus group and their feelings on Title IX
Survey: Why do we not workout?
Observing childhood social settings and its
relation to fitness level

23. Quantitative
• Objective
• Numeric
• Statistical analysis
• Large N’s
• Structured data
collection
• Table/graphs to
display results
Qualitative
• Subjective
• Non-numerical
• Non-statistical
analysis
• Small N’s
• Open ended
data collection
• Narrative for
results

24. The purpose of experimental research
is to investigate cause-and-effect
relationships by manipulating certain
variables to determine their effect on
another variable
• attempts to establish causality
• manipulation of independent variable
• control of extraneous variables is vital
• often uses a control group
• often uses randomization procedures

25. Tends to observe, analyze, and
describe what exists rather than
manipulating the variable under
study
Various types
Causal-comparative
Descriptive
Correlational
Historical

26.  Seeks to investigate cause-and-effect relationships similar to
experimental research
 However, researcher cannot manipulate the independent
variable because it is something the subject already has
• Attribute variable
 Gender
 Ethnicity
 Medical condition
 Example:
• Is there a link between African Americans and
sickle cell anemia
• Location of residence and fitness level
• Comparing diet of those diagnosed with breast
cancer and those without

27.  Seeks to describe specific phenomena or
characteristics of a particular group of
subjects
• Answers the question “what is”
 Does not describe the “how come”
• No manipulation of an independent variable
 Wide range of methodologies
• Surveys
 Children’s TV time and weight
• Direct measurement
 BF% in female vs male track athletes
• Observation
 Motor development in home schooled children
• Interviews
 Feelings about media and physical activity popularity

28. Survey
Developmental
• Longitudinal approach
• Cross-sectional approach
Case Study
Correlational
Normative
• Norm-reference standards
Observational (a.k.a. qualitative)
Causal-comparative (a.k.a. ex post facto)
• Looking at past data for answers to questions

29. Seeks to determine whether, and to
what extent, a relationship exists
between two or more variables
• No manipulation of an independent variable
 Example:
• Association between athletic achievement and self esteem
• Correlation between mandated PE and STAAR scores
• Correlation between athletic performance and sleep
• Relationship among diabetics (2) and knowledge of healthy
eating

31. http://www.youtube.com/watch?v=srB
Fcb8U0p4

34.  Increased sales of ice cream is correlated
with increased deaths from drowning.
 The more firemen sent to the fire, the
greater the damage.
 People who wear XXXL clothing have
increased incidents of heart disease.
 Age is positively correlated with facial
wrinkles.
 Age is negatively correlated with amount
of time spent Googling Justin Beiber.

35.  Seeks to explore events and information
from the past in order to provide a better
understanding of the present with
implications for the future
• Answers the question “what was”
 Limited to synthesis and interpretation of
data that already exists
 Examples:
• Researching past ticket sales and motivation in buyers to determine
whether an increase in price can effect future ticket sales.
• Excitement of certain events during Olympics to determine future site
and future Olympic features
• Past exercise interventions with those diagnosed with schizophrenia

36. Descriptive epidemiology –
• seeking to identify patterns or trends in
disease, injury, or death
Analytic epidemiology –
• seeking to determine causation of disease,
injury, or death
Common in public health fields

37.  Cohort studies
• prospective studies – a study that begins with a
group of people (a cohort) and follows them over
time
• Subsequent status evaluations with respect to
disease or outcome are conducted to determine
which initial participants risk factors are
associated with it
• Advantages
 Subjects in cohorts can be matched which limits
influence of confounding variables
 Standardization of criteria /outcome is possible
 Easier and cheaper than RCT

38.  Case-control studies
• retrospective studies – a study comparing a group
who already have a condition of interest to a
group that does not
 Case group – the group with the characteristic of
interest (e.g., cancer)
 Control group – the group without the characteristic of
interest
• No intervention is attempted
• Advantages
 Good for studying rare conditions
 Less time needed to complete the study
 Look at multiple risk factors simultaneously
 Useful to establish and association

39.  A study design that randomly assigns
participants into an experimental group or
control group. The only expected difference is
the outcome variable being studied
 Advantages:
• Good randomization will wash out population bias
• Easier to blind than observational studies
 Disadvantages:
• Expensive – time and money
• Volunteer bias
• Does not reveal causation

41. • Quantitative means of reanalyzing the results from
a large number of research studies in an attempt
to synthesize findings
• More than merely a review of related literature
• In meta-analysis, each research study contributes
a data point to the subsequent analysis, much like
an individual participant in a descriptive or
experimental research study
Data as part of the entire analysis = individual participants data as part of the
entire research study

42. 1. Compile references
• There must be a substantial number
of research studies available on a
topic
• Requires means, standard deviations,
correlations, etc. published
2. Determine inclusive criteria
• E.g., published in last 10 years or N >
30
3. Review each study
• Record information needed to
calculate ES from each study

43. 4. Decide which studies to use
5. Do the meta-analysis
• Calculate the effect size for each
study
• Generate summary statistics for
effect sizes
• Interpret results
6. Report the results

44. Not the ultimate answer
Does not differentiate the quality
of studies
Combines unlike studies with too
much variability (i.e., mixing apples
and oranges)

46.  A very specific statement which clearly
identifies the problem being studied
• Identify the key variables
• Give some information about the scope of the
study
• Formulation of problem statement takes place
after an initial review of related literature and the
distillation process
• This is the purpose of the research

47. “The problem of this study is to …”
“This study is concerned with …”
“This study is designed to …”
“The purpose of this investigation is to
…”

48. 1.The problem was to investigate the effects of
exercise on blood lipids among college-age
females.
2.This study was designed to determine the
relationship between stability performance and
physical growth characteristics of preschool
children.
3.The present study was designed to identify those
characteristics which differentiate between students
who binge drink and those that do not.
4.The problem of the study was to determine if there
was a relationship between self-efficacy and self-
reported alcohol usage among middle-aged adult
females.

49.  Limitations focus on potential weaknesses of
the study
 Examples include
• sampling problems
 representativeness of subjects: low # of subjects, subjects lying
• uncontrolled factors and extraneous variables
 Weather, suspended funding, etc.
• faulty research design and techniques
 Length of study not long enough, participants adapted to study
protocol
• reliability and validity of measuring instruments
 Blood work sampling can have low validity
1. The accuracy of the results was dependent on the participants
adhering to the intervention protocols (i.e., consuming the proper
antioxidants and the correct amount each day).
2. The participant’s truthfulness on the compliance check sheet.

50.  Possible shortcomings of the study . . .
usually cannot be controlled by the
researcher
• the researcher will, of course, try to eliminate
extremely serious weaknesses before the study is
commenced
 May be a result of assumptions not being
met
• Assume subjects follow protocol
 No study is perfect; the researcher
recognizes the weaknesses

51.  A variable is a characteristic, trait, or
attribute of a person or thing that can be
classified or measured
• Attitude
• Gender
• Heart rate
• Hair color
 Exclusion and Inclusion criteria for
choosing participants
• Excluded-smokers, previous injury, male, etc.
• Included-ages 6-18, currently on BC, healthy BMI,
etc.

52. Quantitative – measured numerically
• Age
• Weight
• BMI
Qualitative – categorical in nature
• Gender
• Ethnicity
• Level of Education

53.  A variable that is presumed to influence
another variable; the variable under
study or the one that the researcher
manipulates
 Two types
• Active – variable is actually manipulated
 Exercise Intensity
 Diet
• Attribute- cannot be manipulated because it is
preexisting trait; sometimes called a “categorical”
variable (Research type: casual comparative)
 Race
 Gender

54. The variable that is expected to
change as a result of the manipulation
of the independent variable; that
which is measured in a study

55.  Independent
Variable
• The variable that is
varied or
manipulated by the
researcher
• It is the presumed
cause
 Dependent Variable
• The response that is
measured
• It is the presumed
effect
• Depends on the
outcome of the
independent
variable

56.  Effects of vitamin C on life span:
• In a study whether taking vitamin C pills daily
make you live longer, researchers will dictate the
vitamin C intake of a group of people over time.
One part of the group will be given vitamin C pills
daily. The other part of the group will be given a
placebo pill. Nobody in the group knows which
part they are in. The researchers will check the life
span of the people in both groups.
• Here, the dependent variable is the life span and
the independent variable is the vitamin C.
http://en.wikipedia.org/wiki/Dependent_and_independent_variables

57. Effect of drug dosage on symptom
severity
• In a study of how different doses of a drug
affect the severity of symptoms, a researcher
could compare the frequency and intensity
of symptoms when different doses are
administered.
• Here the independent variable is the dose
and the dependent variable is the
frequency/intensity of symptoms.
http://en.wikipedia.org/wiki/Dependent_and_independent_variables

58.  "There will be a statistically significant
difference in graduation rates of at-risk high-
school seniors who participate in an
intensive study program as opposed to at-
risk high-school seniors who do not
participate in the intensive study program.“
 IV: Participation in intensive study program.
DV: Graduation rates.

59. A study is conducted measuring the
effect of education on income or
wealth.
• the DV is level of income/wealth and the IV is
the education level of the individual.

61.  You will need to understand what has
already been written about a topic before
you can ask a new question or develop a
new way of answering an old question
• Past literature can help pinpoint exactly what you
want to research and your statement of purpose
• Past literature can help you to develop a successful
research proposal
• Past literature used in your review can be similar, or
have differences that allow you to think outside the
box
• Past literature can help to determine if there is a gap
in the specific topic or method you wish to use

62. Purposes of the review will help the
researcher to:
• Gain an understanding of previous research
work
• Develop a theoretical understanding of the
topic
• Distill the question into a specific problem
• Develop a research plan (methods)
 Research approach and design
 Procedures and instrumentation
• Identify a question

63. Once the basic question has been
identified, you need to consult the
literature to assist in fully defining the
problem
• Conceptual literature
• Related research
Serves as the basis for hypothesis
development

64. Important to most research studies
Tentative explanation of the
outcome of a research problem
• The hypothesis includes a decrease in
fat percentage and depression during
an exercise/nutrition education
program.

65. Research Hypothesis – An “educated
guess” or tentative proposition
regarding the possible solution or
explanation to the problem being
studied
• based on theory or previous research
THERE IS A SIGNIFICANT DIFFERENCE IN ANXIETY LEVELS OF
CHILDREN WITH HIGH IQ AND THOSE WITH LOW IQ

66.  Null or Statistical Hypothesis - A
hypothesis of “no difference or no
relationship”
• primary use is for statistical testing
• hypothesis which says the independent variable has no
effect on the dependent variable
• does not necessarily reflect the researcher’s expectations
• Believe this until proven otherwise
THERE IS NO SIGNIFICANT DIFFERENCE IN ANXIETY LEVELS OF
CHILDREN WITH HIGH IQ AND THOSE WITH LOW IQ

67. The Research Hypothesis is
transformed into a Statistical or Null
Hypothesis (Ho)
• This is done so that statistical tests can be
employed that will determine whether the
findings are statistically significant or can
be attributed to chance
• The results of the statistical test will enable
the researcher to accept or reject the null
hypothesis

68.  We want to be as sure as possible that
our theories are as correct as possible.
 We want to avoid a fluke!
• If we give out a new drug and by chance
people get better (when the researcher
knows it is inactive), then it is a fluke
 So, statistical testing tests the
probability that your null hypothesis is
true or not.

69. If the null hypothesis is accepted, then the
researcher rejects the research hypothesis and
concludes there is no difference between the
groups
If the null hypothesis is rejected, then the research
hypothesis is affirmed and the researcher
concludes there is a significant difference
between the groups

70. It is hypothesized that children taught
by teaching method A will perform
better on a reading achievement test
than children taught by method B

71. There will be no significant difference in
reading performance between
students taught by method A and
students taught by method B
or
Teaching method has no effect on the
reading performance of students

73. The nature of the study will determine
what type of data are required to
answer the question and the method
of collecting these data
Multiple techniques may be used in a
single study

74.  Observation - the researcher may
watch the research participants
perform and record relevant
information about them
 Measurement - the researcher may test
the research participants or apply a
device to measure certain qualities
 Questioning - the researcher may ask
the research participants questions to
obtain information

75.  a study in which a researcher simply
observes behavior in a systematic
manner without influencing or
interfering with the behavior
• Direct observation
• Indirect observation
• Participant observation
Example: observe patient’s chewing during a
meal with and without dentures

76.  Researcher directly observes
research participants
 Research participants usually know
they are being observed
 Problem?:
• Researcher’s presence might change the
way the research participants act
Observing subjects as they run a mile; many
say the pressure can increase/decrease
motivation and performance

77. Research participants are filmed or
videotaped
Researcher views tape
Children observed while they interact in
a jungle gym alone, with same gender,
with group of children, with adults.

78. The observer participates in the
research setting with the research
participants, often spending
considerable time in the natural setting
developing field notes
Qualitative research methodology
Observe the daily physical activity in a
specific population and taking field
notes

79. Scaling is the process of assigning
numbers to the various levels of a
particular concept that we wish to
measure. Thus, a scale provides an
indirect measure of the concept of
interest
• Rating of perceived exertion (RPE): 6-20
Scales can be used to obtain
information on almost any topic,
object, or subject.
• Attitude, opinion, behavior, performance,
and perception are frequently measured by
some type of scale

80.  Rating Scale
• Selected a score from 1-10
 Semantic Differential Scale
• Clean - - - - - - - Dirty
 Rank Order Scale
• Rank the products in order of perceived quality
 Likert Scale
• Strongly agree-agree-neutral-disagree, strongly disagree

81. Individual items are judged on a single
dimension and scored on a linear scale
or continuum by selecting a numerical
or verbal point on the scale that
corresponds to their impression of the
item

82. How important to you is each of the issues listed below:
Extremely Extremely
Unimportant Important
1 2 3 4 5
The protection of endangered species of animals ____
The improvement of the quality of the air ____
The provision of social services to those in need ____

83. Concepts No Moderate Greatest
Importance Importance Importance
Staff Discipline ___ ___ ___
Communication ___ ___ ___
Goal Setting ___ ___ ___
Public Relations ___ ___ ___
Computer Use ___ ___ ___
Administrative Concept Scale

84. Items are ranked, usually in terms of
preference or importance, relative to
each other. This forced ranking results
in ordinal scores, thus limiting the
statistical treatment of the scores
 the intervals between score points are not always
equal
The number of items to be ranked
should be less than 10, to avoid making
the task too difficult

85. Please rank the brands of beer listed below in
order of preference, with a 1 being the brand
you most prefer, 2 being your second choice,
and so forth.
____ Budweiser
____ Coors
____ Miller
____ Corona

86. A very popular scaling technique
which measures the respondent’s
degree of agreement or disagreement
on an issue, opinion, or particular belief
The continuum of response typically
runs from SA , A, U, D, to SD
Responses to a Likert scale can be
considered to be interval level scores,
thus allowing scores to be summed
and treated statistically

87. Pick a number from the scale to show how
much you agree or disagree with each
statement:
1 Strongly agree
2 Agree
3 Undecided
4 Disagree
5 Strongly disagree
College athletes should be paid ____
A woman’s place is in the home ____
Participating in sports is all about winning ____

88.  Wide variety of methods that involve
questioning the research participant
• Questionnaires
 Structured
 Unstructured
 Checklist
• Interviews

89.  Survey research - most common type of
descriptive research
 Usually self-report questionnaires pertaining
to attitudes, behaviors, practices, likes,
dislikes, etc.
• Food Frequency Questionnaire (FFQ)
 May be mailed, distributed by the researcher
or completed online
 Many formats
• Have you completed a survey in the past year?

90. Essentially an oral questionnaire
• 24 Hour Recall
May be personal or telephone
interviews
• Structured interview
• Unstructured interview

91. Essentially an interview with groups of
people
Designed to stimulate participants free
expression of feelings, beliefs, etc.
Requires a skilled facilitator to guide
discussion

92. What type of data is needed to answer
the research problem?
Factors to consider
• Demands on the research participant
• Costs in terms of money, energy, and time
• Ability of the researcher to handle the
selected technique, including the data
analysis

93.  May include any mechanical or
electronic equipment, physical
performance task, paper-and-pencil
test or scale, as well as a questionnaire
designed to collect data on the
variable of interest
 Researcher’s choice of instrument
involves deciding if
• one already exists that can be used as is
• if one exists but needs to be revised
• if one needs to be developed

94.  Thoroughly review the literature
 If instrument is found, assess suitability:
• Reliability - consistency with which it measures
• Validity - measures what it is suppose to
measure
 Reliability and validity of an instrument are often
specific to the age, gender, characteristics of
subjects on which it is used
 Without acceptable reliability and validity, the data
are of no use in answering the research question
• Objective - free from scorer bias
• Appropriateness to current study
• Ease of administration and scoring

96. http://www.youtube.com/watch?v=fm
EDdVEwkHc

97.  Nazi Experimentation in WWII
• “Medical Experiments”
 Prisoners coerced into participating & resulted in
death, disfigurement & disability
 Bone, muscle, nerve transplantation
 Head/hammer injury experiment
 Hypothermia studies
 Mustard gas exposure
• Nuremberg War Crime Trials
• Nuremberg Code – basic principles
to govern research involving human subjects
 Tuskegee Syphilis Study
• Public Health Service project related to untreated
syphilis
• Highlights deception and informed consent
 Human radiation experiments

98.  Nuremberg Code (1947) – first set of
guidelines
 Helsinki Declaration (1964) –
medical research
 Belmont Report (1979) –
fundamental document for current
federal regulations in US
 Common Rule (1991) – 45 C.F.R. 46
• Federal rules that govern research
involving human participants in the US
 Institutional Review Boards (IRB)

99.  Arguably the most important ethical
standard
 Refers to telling research participants
about all aspects of the research that
might reasonably influence their
decision to participate
 Four important elements
1. Subjects are fully aware of nature and purpose
of research project
2. Consent is voluntarily given
3. Person has legal capacity to give consent
4. Responsibility for obtaining consent rests with
researcher

100. Particular precautions must be taken
to protect the welfare of subjects that
might be considered especially
vulnerable or at risk for some reason
The following types of subjects might
be considered to be vulnerable:
children, handicapped, cardiac rehab patients,
welfare recipients, prisoners, pregnant women,
patients in a mental hospital, etc.

101.  Privacy – refers to the capacity of
individuals to control when and under
what conditions others have access to
their behaviors, beliefs, and values
• Participants stance
 Confidentiality – refers to treating subject
information or responses in a manner so
that it is not linked to any specific
individual who participated in a study
• Researchers responsibilities
 Normally addressed through informed
consent

102.  IRBs established by federal mandate to
assure compliance with governmental
regulations
 IRBs have authority to approve, require
modifications, or disapprove research
 IRB approval required before any
aspect of the research involving human
subjects may commence

103.  According to the U.S.
Public Health Service . . .
• “Misconduct” means
fabrication, falsification,
plagiarism, or other practices
that seriously deviate from
those that are commonly
accepted within the
scientific community for
proposing, conducting, or
reporting research

104.  Researcher is responsible for his/her subjects
 Researcher is responsible for his/her own actions and
those of any research aides
 Subjects must provide informed consent
 Researcher protects subjects from harm, danger,
and discomfort
 Maintain anonymity and confidentiality
 Subjects should not be coerced
 Researcher has responsibility after the investigation is
complete to safeguard subject data
 Honest disclosure of results

105. Selection of Research
Participants: Sampling
Procedures

106.  This is considered highly important in
social and behavioral research
 Three basic questions to consider:
1. Are the research participants appropriate for
the research question?
2. Are the research participants representative
of the population of interest?
3. How many research participants should be
used?

107.  Population – refers to an entire group of people or
elements having one or more common characteristics
 Target Population – the group that is the focus of your
research
 Accessible Population – members of the population that
you can reach
 Sample – a small subgroup of a population of interest
thought to be representative of that population
• Sampling Unit – one member of your population
 Sampling – the process of selecting a subgroup or
sample of the population

108.  Random Selection
• The purpose is to enable the researcher to
generalize the results to a larger population.
Thus, the researcher is concerned about the
“representativeness” of the subjects in the
sample
 Random Assignment
• The purpose is to enable the researcher to
assume that groups are “equivalent” at the
beginning of the study. This adds control to a
study; it has nothing to do with the selection of
the sample

109.  Probability Sampling
• Sampling techniques in which the probability of
selecting each participant is known
• Utilizes random processes, but does not
guarantee the sample is representative of
population
• Estimates of sampling error are possible
 Non Probability Sampling
• Samples are not selected at random
• Difficult to claim sample is representative of population
• You can’t estimate the sampling error
• Intact groups, volunteers

110. Probability Sampling
• Simple random sampling
• Stratified random sampling
• Systematic sampling
• Cluster sampling
Non Probability Sampling
• Purposive sampling
• Convenience sampling

111.  With simple random sampling, every member of the
population has an equal probability of being
selected for the sample.
 Also, the selection of one member of the population
does not affect the chances of any other member
being chosen (equal and independent)
 Example: The population might be all hospitals in the
U.S. that perform heart bypass surgery.
 Usual procedure:
• Fishbowl technique
• Table of random numbers
• Computer generated sampling

112.  An alternative to simple random sampling in which the
sampling units are selected in a series according to some
predetermined sequence. The origin of the sequence
should be controlled by chance
 The researcher will choose 1/kth of the sampling frame
with k being any constant. The first sampling unit is
randomly selected by the investigator. Thereafter, every
kth unit in the sampling frame is chosen
• Put names in alphabetical order and choose every 5th person
 Simple random sampling is to be preferred, but
systematic sampling is a practical and useful
approximation to random sampling that is easier to
perform

113.  When members of the sample are
purposively selected because they
possess certain traits that are critical to
the study
 Example: Selecting celiac patients for
an oat sensitivity study

114.  Refers to selecting research participants
on the basis of being accessible and
convenient to the researcher
 Often involves use of volunteers
 Example: Using fellow graduate students
as research participants

115.  Regardless of size, the crucial factor is
whether or not the sample is
representative of the population, thus
how the sample is selected
 Points to consider regarding sample size:
• Nature of the study
• Statistical considerations
• Variability of population
• Number of treatment groups
• Practical factors

116.  Descriptive, correlational, or
experimental
• Descriptive and correlational studies typically
should have more research participants
• Experimental studies often employ fewer
research participants

117. How do you want to analyze the data?
What statistical application will be
used?
Generally N=30 is minimum needed to
meet assumptions of many statistical
procedures

118. Sample size is inversely related to
sampling error
• The larger the sample size, the smaller the
sampling error and the greater likelihood that
the sample is representative of the population
Little variability – small sample will
suffice
High variability – sample size will be
larger

119.  Each research participant is randomly
assigned to one of the various treatment
groups
 Each subject participates in only one group
 Avoids carry-over effect due to cross over
 Test the effects of caffeine on cognitive
function:
• one group of subject's math ability might be tested
after they consume caffeine
• And another group of subject’s math ability tested
after they consume a placebo

120.  Subjects participate in more than one group
(treatment condition)
 In the simplest example, each research
participant would be assigned to each level
of the independent variable and then is
measured after receiving the treatment
 Counterbalancing is often used to control for possible
order effect
 Wash out times may help avoid carry-over effect
 Cross-over Design
• to test the effects of caffeine on cognitive function, a subject's
math ability might be tested once after they consume caffeine
and after they receive a placebo

121. Single Blind Study:
• participants are unaware of whether they are
receiving the experimental or control
treatment
Double Blind Study
• participants and researcher are unaware of
the groups and who is receiving the
experimental or control treatment

123. Data:
• Measures, scores, &
other info collected
in a research study.
• Refers to scores of
participants for a
variable
 Change in BMI when a
reduced calorie diet is
followed

124.  Why is data & statistics important to
you?
◦ Useful to know data analysis techniques in
selecting the most appropriate one for your
own research
◦ Useful when reading your Literature Review
articles

126.  Overall performance & characteristics
 Make comparisons between groups
• Comparing one group from another or more
 Low Fat vs Low Carb: Compare weight loss
 One group will prevail from the others
 Make comparisons within groups
• Comparing data gathered from one group
 Mediterranean diet intervention: Compare
subjects within this group on lower CV risk factors
and weight
 To see the percentage of change from this one group

127. 1.Select the appropriate statistical
technique
• In your procedures, you will be determining the
techniques to use. Where can you get ideas?
2.Apply the technique
• Gather your numbers or results and input into a
data analysis program such as SPSS
 Using a computer program helps to reduce time and
mistakes from human error (plus, I suck at math!)
3.Interpret the result

128.  Statistics used to describe characteristics of
a group.
 What are the characteristics you are looking
at in your research?
• Weight loss
• Recovery rate after surgery
• Biochemical Improvement
• Performance after various sleep time
• Mood after exercising

129.  Descriptive use of statistics is used when
measuring a trait or characteristic of a group
without an intention to generalize that
statistic beyond that group.
• Mean: Average
• Median: Midpoint
• Mode: Most frequent
• Standard deviation
• Range of scores
 Inferential use of statistics occurs when one
makes generalizations or inferences from a
smaller group to a larger group.

130.  Variety of computer programs for
statistical computations; mainframe
and desktop
› SPSS
› SAS
› Statview
› Excel
 Fast, easy to use, widely available

131.  The alpha level is the chance the
researcher is willing to take that the
rejection of the null hypothesis was a
mistake.
 It is typically reported as a “p value”,
such as “the results were significant at
p < .05”, or p < .01, or p < .001