Given the set of test scores: 42, 72, 74, 78, 80, 80, 85, 88, 92. If the outlier is removed, which statement is true? Select all that apply. Choose all that apply:

The standard deviation decreases.

The mean increases.

The median decreases.

The range increases.

Standard deviation decreases and mean increases

Step-by-step explanation:

The test scores are:

42, 72, 74, 78, 80, 80, 85, 88, 92

Mean = (42 + 72 + 74 + 78 + 80 + 80 + 85 + 88 + 92)/9 = 76.77

Median is 5th term which is 80

Range is highest score - lowest score = 92 - 42 = 50

Standard deviation from an online calculator gives 13.69

Now,we want to know what happens to those values when the outlier is removed. The outlier in this case is 42 because it is not consistent with other scores which range from 72 - 92.

Thus,the new set of scores are;

72, 74, 78, 80, 80, 85, 88, 92

New Mean = (72 + 74 + 78 + 80 + 80 + 85 + 88 + 92)/8 = 81.125

New Median will be the average of the 4th and 5th term which is (80 + 80)/2 = 80

New Range = 92 - 72 = 20

New Standard deviation from an online calculator gives 6.39

From the comparison above when the outlier is removed, we can say that;

- Mean increases

- remains the same

- Range decreases

- standard deviation decreases