The speed vehicles traveled on a local road was recorded for one month.The speeds ranged from 48 km/h to 63 km/h with a mean speed of 57 km/h and a standard deviation of 6 km/h.The quartiles and median speeds were 51 km/h,60 km/h,and 54 km/h.Suppose increased patrols reduced speeds by 7%.Find the new mean and standard deviation.Express your answer in exact decimals.
A)Mean: 53.01 km/h,SD: 5.58 km/h
B)Mean: 53.01 km/h,SD: 6 km/h
C)Mean: 60.99 km/h,SD: 6.42 km/h
D)Mean: 3.99 km/h,SD: 0.42 km/h
E)Mean: 60.99 km/h,SD: 6 km/h

Question

Quizplus · Accepted Answer

To find the new mean speed, we need to subtract 7% from the original mean speed.

New Mean Speed = 57 km/h - 0.07(57 km/h) = 53.01 km/h

To find the new standard deviation, we can use the formula:

New SD = Old SD * (1 - 0.07) = 6 km/h * 0.93 = 5.58 km/h

Therefore, the correct choice is A.

The Speed Vehicles Traveled on a Local Road Was Recorded