Question

The police department of a major city needs to update its budget. For this​ purpose, they need to understand the variation in their fines collected from motorists for speeding. As a​ sample, they recorded the speeds of cars driving past a location with a 25 mph speed​ limit, a place that in the past has been known for producing fines. The mean of 100 representative readings was 28.77 ​mph, with a standard deviation of 3.42 mph.

​a) How many standard deviations from the mean would a car going the speed limit​ be?

​b) Which would be more​ unusual, a car traveling 36 mph or one going 16 ​mph?

​a) A car traveling at the speed limit is ____ standard deviations from the mean.

Answer 1

a) number of standard deviation =(M-mean)/standard deviation =(28.77-25)/3.42 =1.10 standard deviation from the mean

b)

16 ​mph would be more unusual , since this is farther from the mean value than 36 mph.