Download Find Measures of Central Tendency

You have already found the mean or average
of a data set. (Lesson 2–5)
• Use the mean, median, and mode as
measures of central tendency.
• Choose an appropriate measure of central
tendency and recognize measures of
statistics.
• measures of central tendency
For a list of numerical
data, numbers that can represent the whole set of data (ex. Mean,
median, mode)
• mean
The sum of the data divided by the number of items in the
data set, also called average
• median
• mode
In a set of data, the middle number of the ordered data, or
the mean of the two middle numbers
The number that occur(s) most often in a set of data
Find Measures of Central Tendency
MOVIES Find the mean, median,
and mode of the data in the table.
The mean is 432.1 million.
Find Measures of Central Tendency
To find the median, order the numbers from least to
greatest.
373, 377, 380, 404, 423, 431, 435, 436, 461, 601
There is an even number of items. Find the mean of the
two middle numbers
The median is 427 million.
There are no repeated values, so there is no mode.
Answer: mean: $432.1 million, median: $427 million,
no mode
TEST SCORES The test scores for a class of nine
students are 85, 93, 78, 99, 62, 83, 90, 75, 85. Find the
mean, median, and mode of the test scores.
A. mean, 73.9; median, 85;
no mode
B. mean, 83.3; median, 85;
mode, 85
C. mean, 750; median, 62;
mode, 85
D. mean, 83.3; median, 62;
mode, 85
A.
B.
C.
D.
A
B
C
D
Nabuko has test scores of 80, 85, 72, and 91. If her
next score is 82, which of the following statements
would be true?
A The mean increases and the median decreases.
B The mean is unchanged and the median decreases.
C Both mean and median increase.
D Both mean and median decrease.
Read the Test Item
You need to determine which statement would be true if
Nabuko’s score on her next test is 82.
Solve the Test Item
The mean of the four scores is
Adding another score of 82 will not change the mean.
You can eliminate choices A, C, and D.
Arrange the numbers from least to greatest, first with
four days and then with five days.
Find the median to check that choice B is correct.
72, 80, 85, 91 The median is 82.5.
72, 80, 82, 85, 91 The median is 82.
So, the median would decrease.
Answer: The correct answer is B.
Sheila has test scores of 85, 82, 70 and 90. If her
next score is 78, which of the following statements
would be true?
A. The mean increases and the
median decreases.
B. The mean is unchanged and
the median decreases.
C. The mean and the median
increase.
D. The mean and the median
decrease.
A.
B.
C.
D.
A
B
C
D
Choose an Appropriate Measure
SURVEYS Mai took a poll in her class to see how
many times her classmates visited the local
amusement park during summer vacation: 4, 0, 2, 3,
2, 4, 1, 2, 1, 2, 3, 2, 2, 0. What measure of central
tendency best represents the data? Then find the
measure of central tendency.
Answer: The set of data has many repeated values,
so the mode would be the best. The most
frequent value is 2.
BOWLING Jenny’s bowling scores are 108, 138, 140,
142, 139, 138, and 145. Which measure of central
tendency best represents the data?
A. mean
B. median
C. mode
D. cannot be determined
A.
B.
C.
D.
A
B
C
D
Different Points of View
SALARIES The weekly salaries for the employees
at Bob’s Book Store are $600, $600, $625, $1250,
$1800. Which measure of data should Bob’s Book
Store’s manager use to show new employees that
the salaries are high?
Mean:
Median: 600, 600, 625, 1250, 1800
625
Mode: 600
Different Points of View
The greatest measure is the mean.
Answer: The manager would want to use the highest
measure for salary. So, the manager would
want to use the mean, $975.
EXERCISE The number of hours spent exercising
each week by a group of women are: 1, 6, 4, 2, 1, and
8. Which measure of central tendency should a
person use to show that women do not spend
enough time exercising?
A. mode
B. median
C. mean
D. cannot be determined
A.
B.
C.
D.
A
B
C
D