Question

A teacher gives a test in which the average of the test scores is 68 and the standard deviation is 14. Realizing that the test was probably too difficult, the teacher decides to scale the tests by adding 10 points to all scores. What is the mean and standard deviation of the scaled test scores?

Answer 1

Mean = 78 ;

Standard deviation = 14

Explanation:

Given that:

Mean score = 68

Standard deviation = 14

When a constant value is added to the individual value of a dataset, the new mean value will become the sum of the initial mean value and the constant term added to the values.

Constant Added score = 10

The mean of scaled test score will be:

Mean score + constant added score

68 + 10 = 78

The standard deviation remains unchanged ; Hence, standard deviation = 14