Question

Suppose that a police officer measured the speed of cars on a highway for an hour. The average speed of the cars was 71.3 and the standard deviation was 5.23. However, since the radar gun was biased, 4.9 is added to every observation in the dataset. What will the new standard deviation be?

Answer 1

The new mean is 76.2

Explanation:

Given

Given

Old mean = 71.3

Every observation is increased by 4.9.

Let the data set has N entries, then

The new mean would be

(71.3 *N + 4.9*N)/N

The new mean = 71.3 + 4.9 = 76.2