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1. STAT Homework assignment week 2 complete solutions correct answers key
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(Total 9 problems)
7. For the data from the 1977 Stat. and Biom. 200 class for eye color, construct:
a. pie graph
b. horizontal bar graph
c. vertical bar graph
d. a frequency table with the relative frequency of each eye color
Eye Color Number of Students
Brown 11
Blue 10
Green 4
Gray 1
9. Which of the box plots on the graph has a large positive skew? Which has a large
negative skew?
6. You recorded the time in seconds it took for 8 participants to solve a puzzle.
These times appear below. However, when the data was entered into the
statistical program, the score that was supposed to be 22.1 was entered as 21.2.
You had calculated the following measures of central tendency: the mean, the
median, and the mean trimmed 25%. Which of these measures of central
tendency will change when you correct the recording error?

2. Time (seconds)
15.2
18.8
19.3
19.7
20.2
21.8
22.1
29.4
8. You know the minimum, the maximum, and the 25th
, 50th
, and 75th
percentiles of a
distribution. Which of the following measures of central tendency or variability
can you determine? Mean, median, mode, trimean, geometric mean, range,
interquartile range, variance, standard deviation
ADHD Treatment (AT) case study
30. (AT) What is the mean number of correct responses of the participants after taking
the placebo (0 mg/kg)?
31. (AT) What are the standard deviation and the interquartile range of the d0
condition?
Use this case study for questions 30 and 31:
Treatment Effects of a Drug on Cognitive Functioning in Children
with Mental Retardation and ADHD
RESEARCH CONDUCTED BY: Pearson et al. (2003, see reference below)
CASE STUDY PREPARED BY: David Lane and Emily Zitek

3. OVERVIEW
This study investigated the cognitive effects of stimulant medication in
children with mental retardation and Attention-Deficit/Hyperactivity
Disorder. This case study shows the data for the Delay of Gratification (DOG)
task. Children were given various dosages of a drug, methylphenidate (MPH)
and then completed this task as part of a larger battery of tests. The order
of doses was counterbalanced so that each dose appeared equally often in
each position. For example, six children received the lowest dose first, six
received it second, etc. The children were on each dose one week before
testing.
This task, adapted from the preschool delay task of the Gordon Diagnostic
System (Gordon, 1983), measures the ability to suppress or delay impulsive
behavioral responses. Children were told that a star would appear on the
computer screen if they waited “long enough” to press a response key. If a
child responded sooner in less than four seconds after their previous
response, they did not earn a star, and the 4-second counter restarted. The
DOG differentiates children with and without ADHD of normal intelligence
(e.g., Mayes et al., 2001), and is sensitive to MPH treatment in these
children (Hall & Kataria, 1992).
DESIGN ISSUES
This is a repeated-measures design because each participant performed the
task after each dosage.
DESCRIPTIONS OF VARIABLES
VARIABLE DESCRIPTION
d0 Number of correct responses after taking a placebo
d15 Number of correct responses after taking .15 mg/kg of the drug
d30 Number of correct responses after taking .30 mg/kg of the drug
d60 Number of correct responses after taking .60 mg/kg of the drug
REFERENCES
Gordon M (1983), The Gordon Diagnostic System. DeWitt, NY: Gordon Systems

4. Hall CW, Kataria S (1992), Effects of two treatment techniques on delay and vigilance
tasks with attention deficit hyperactive disorder (ADHD) children. J Psychol
126:17-25
Mayes SD, Calhoun SL, Crowell, EW (2002), The Gordon Diagnostic System and
WISC-III Freedom from Distractibility index: Validity in identifying clinic-
referred children with and without ADHD. Psychol Rep ,91, 575-587.
Pearson DA, Santos CW, Roache JD, Casat CD, Loveland KA, Lachar D, Lane DM,
Faria, LF, Cleveland LA (2003), Treatment effects of methylphenidate on
behavioral adjustment in children with mental retardation and ADHD. J Am
Acad Child Adolesc Psychiatry, 42, 209-216.
Pearson, D.A., Santos, C.W., Jerger, S.W., Casat, C.D., Roache, J., Loveland, K.A.,
Lane, D.M., Lachar, D., Faria, L.P., & Getchell, C. (2003) Treatment effects of
methylphenidate on cognitive functioning in children with mental retardation
and ADHD. Journal of the American Academy of Child and Adolescent
Psychiatry, 43, 677-685.
LINKS Methylphenidate
78. Twenty-five randomly selected students were asked the number of movies they
watched the previous week. The results are as follows:
a. Construct a histogram of the data
b. Complete the columns of the chart.
Use the following information to answer the next two exercises: Suppose one hundred
eleven people who shopped in a special t-shirt store were asked the number of t-shirts
they own costing more than $19 each.