There are three main measures of central tendency used to describe data sets: mean, median, and mode. The mean is the average value calculated by dividing the sum of all values by the total number of values. The median is the middle value when all values are arranged in order. The mode is the value that occurs most frequently in the data set. Examples are provided to demonstrate calculating and interpreting each measure of central tendency.

1. Measures of Central
Tendency

2. A MEASURE OF CENTRAL TENDENCY is a way to find the
value(s) in the MIDDLE of a set of numbers, or the AVERAGE.
There are 3 measures of central tendency that
we use for different situations:

3. 1) MEAN: The true quot;averagequot; of a set of values.
The sum divided by the quantity.
EX What is the mean of the following values?
6, 7, 19, 9, 51

4. 2) MEDIAN: The value(s) in the MIDDLE of a
set values, that are IN ORDER.
EX What is the median of the following values?
7, 1, 16, 9, 8

5. EX What is the median of the following values?
17, 14, 10, 11, 13, 18

6. 3) MODE: The value(s) which occur most often.
It has to occur at least two times.
There can be more than one mode.
EX What is the mode of the following values?
8, 100, 45, 8, 7, 100, 9, 4, 1

7. pg.92; Small Group Activity (a ­ d)
a)
0 2 10
4 6 8 12
# of letters in each word

8. b) mean = sum / 32 median = 4 mode = 2
= 4.81
c) least appropriate = mode, most appropriate = mean
d) mean = average length of a word.
median = quot;middlequot; number of letters of a word, when arranged in order.
mode = word with 2 letters shows up the most.

9. HOMEWORK
pg.93. #1 ­ 8