Measures of Central Tendency

1
Measures of Central Tendency
SECTION 4.4
2
mean
The _____ of a data set is the quotient when the
sum of all of the elements is divided by the
total number of elements.
The __________ of a data set is the middle number
in the set when the elements are placed in
numerical order. If there are an _______ number
of elements, the _________ is the average of the
two middle numbers.
median
odd
median
The _______ of a data set is the element, if any,
that occurs most often. There may be no mode,
one mode, or several modes.
mode
range
The _________ of a data set is the difference
between the greatest and least values in the set.
3
Example 1 Find the mean, median, mode, and
range for each set of data.
3, 5, 8, 5, 8, 7, 16, 10, 2, 7, 1, 5, 6, 1
A.
Mean
1
1
2
Divide the total numbers by 2 to find the half
way point.
List numbers from least to greatest.
3
Median
5
5
5
6
7
7
Mode
8
8
Range
10
16
4
160, 100, 150, 125, 125, 150, 114
B.
100
Mean
114
125
125
Choose the 4th number
150
Median
150
160
125
Range
Mode
5
frequency table
A ________________ is a method of displaying data
in which tally marks are used to show how often
each element of the set occurs.
Example 2 Make a frequency table showing the
number of letters in the last names of all the
student in the class.

• . What is the mode? MOST
• . What is the median? MIDDLE
• . What is the mean? AVERAGE
• . What is the range? GREATEST-LEAST

6
Example 3 Cathy has been swimming in the
50-meter butterfly event since she started high
school. During that time, she has kept track of
what place she finished in the event at each meet
she attended. Find the mode, median, mean, and
range of the places finished.
10th
9th
8th
7th
6th
5th
4th
3rd
2nd
1st
Place
Frequency

4
4
12
20
10
24
28
24
27
10

• . What is the mode?
• . What is the median?
• . What is the mean?
• . What is the range?

Pick between the 16th and 17th place.