The speeds of vehicles (in mph) passing through a section of Highway 75 are recorded for a random sample of 150 vehicles and are given below. Test the hypothesis that the speeds are normally distributed with a mean of 70 and a standard deviation of 4. Use a = 0.01.
|
Range
|
40-55
|
56-65
|
66-75
|
76-85
|
> 85
|
|
Number
|
12
|
14
|
78
|
40
|
6
|