Measures of Central Tendency Pretest 1

Question 2. Bill's history marks are: 72, 66, 65, 73, 71, 69, 68, 72.
Find the mean, mode, median and range.

First put all the numbers in numerical order. That would make it easier.

65, 66, 68, 69, 71, 72, 72, 73

Mean= 69.6

Add up all the numbers, you get 556, the sum of all data. Then divide 556 by 8, the number of pieces of data, getting 69.6

Median= 70

The two middle numbers are 69 and 71. Add them together then divide them by two. 140 / 2 = 70

Mode = 72

72 is the most common number.

Range= 8

Subtract 65 from 73. 73 - 65 = 8


A) If he scores 91 on the next test, which measure of central tendency will be most affected? Explain.

65, 66, 68, 69, 71, 72, 72, 73, 91

Mean= 71. 8

Add up all the numbers getting 647. Then divide it by 9, equaling 71.8.

Median= 71

71 is the median because there is an odd number of data pieces in this set, making it easy to identify the median.

Mode= 72

There are two 72's while there are only one of every other number.

Range= 26

Subtract 65 from 91. 91 - 65 = 26


B) If he scores 66 on the next test, Which measure of central tendency will be most affected? Explain.

65, 66, 66, 68, 69, 71, 72, 72, 73


Mean= 69.1

Add all the numbers together to get 622. Divide by 9, equaling 69.1.

Median=69

69 is the median because there is an odd number of data pieces in this set, making it easy to identify the median.

Mode= 66, 72

Since there are two 66's and 72's, this time the modes would be both 66, and 72.

Range= 8

Subtract 65 from 73. 73 - 65 = 8