Statistics - Unit 2 Practice Test

Which of the following quantities is unchanged by adding a constant to each data value in a data set?

I. Mean

II. Median

III. Range

• I and III

• I only

• III only

• I and II

The tables below show the scores of two History Tests: Unit 1 and Unit 2. Calculate the mean, median, and mode and choose the correct description.

Unit 1 Test scores:

80, 67, 92, 85, 71, 94, 100, 65, 73, 96, 55, 73, 100, 95, 81

Unit 2 Test scores:

96, 100, 99, 91, 76, 100, 78, 64, 77, 98, 67, 97, 95, 83, 81

• Both distributions have the same mean and median

• Unit 1 test has a higher mean

• Unit 1 test has a higher median

• Both distributions have the same mode

Which distribution would you expect to be skewed left?

• Age at retirement

• Hotel stay lengths

• Heights of a class of 18 year-olds

• Ages of patients who had braces put on their teeth over the course of a year.

If a distribution is negatively skewed (skewed left) where would the mean and median fall?

• The median is at the center of the distribution, the mean is to the right of median.

• The mean is at the center of the distributions, the median is to the right of the mean.

• The median is the center of the distribution, the mean is to the left of the median.

• The mean is the center of the distribution, the median is to the left of the mean.

Calculate the mean absolute deviation (MAD) of the following set of data? (round to the nearest whole number)

80, 67, 92, 85, 71, 96

• 9

• 8

• 10

• 11

Jim is trying to throw a consistent 85 mph curveball. He is comparing velocity data from 10 pitches last week and 10 pitches this week. The tables are shown below. He computes the mean absolute deviation (MAD) for each week. Which statement is correct?

Last Week's pitches:

81, 85, 85, 87, 80, 79, 77, 79, 85, 85

This week's pitches:

85, 81, 84, 86, 85, 84, 85, 80, 79, 84

• The MAD for last week is larger than this week’s. Therefore, Jim has improved his not curveball consistency.

• The MAD for last week is larger than this week’s. Therefore, Jim has improved his curveball consistency.

• The MAD for last week is smaller than this week’s. Therefore, Jim has improved his curveball consistency.

• The MAD for last week is smaller than this week’s. Therefore, Jim has not improved his curveball consistency.

Calculate the interquartile range of the following distribution.

85, 81, 84, 86, 85, 84, 85, 80, 79, 84

• 4

• 2

• 85

• 7

The interquartile range of 30 data points will contain how many of the data points in it?

• 15

• 8

• 10

• 13

Which set of data has the largest standard deviation? (No calculations required!)

• 20 26 28 30 32

• 20 26 28 30 33

• 89 97 99 100 102

• 89 97 99 101 103

Calculate the standard deviation (population) of the following population of data: 35, 50, 65, 90, 65, 65, 70, 80. Select the closest answer.

• 16

• 18

• 14

• 20