Statistics Practice Exam

The average (arithmetic mean) of 5, 14, and x is 15. What is the value of x?

• 25

• 26

• 27

• 28

Mary has the following scores on 7 quizzes: 84, 79, 83, 87, 81, 94, 87. What was the median score?

• 81

• 84

• 85

• 86

If the average of 7 numbers is greater than 25 and less than 30, which of the following could be the sum?

• 150

• 170

• 190

• 210

Which of the following sets has an average equal to its median?

• {−2, −1, 1}

• {−2, −1, 1, 2, 3}

• {1, 2, 3, 6}

• {1, 2, 3, 4, 5}

Set X has an average of 5. Set Y is created by doubling and adding 3 to each number in X. What is the average of set Y?

• 10

• 11

• 12

• 13

Let A represent the average of all winter monthly heating bills for John's family. What is the result of multiplying A by the number of winter months?

• The average of all heating bills

• The number of winter months

• The total cost of all bills

• The average cost for the year

Which measure is most affected by an outlier in a data set?

• Mean

• Median

• Mode

• Range

What is the range of the following set of numbers: 4, 7, 11, 5, 9?

• 5

• 7

• 6

• 8

A class has 5 boys and 15 girls. If one student is chosen at random, what is the probability of selecting a boy?

• 1/2

• 1/4

• 1/3

• 1/5

A student scored 78, 84, 91, and 87 on four tests. What score must the student get on the fifth test to have an average of 85?

• 87

• 85

• 82

• 89