A highway speed monitor is located on the side of the road that has a speed limit of 45 mph. The system records the speeds of passing vehicles. The data below shows the speeds of the first 9 cars that pass.

46 56 45 44 45 61 55 53 39

What is the standard deviation, to the nearest tenth, based on the posted speed limit, 45 mph?

Question

A highway speed monitor is located on the side of the road that has a speed limit of 45 mph. The system records the speeds of passing vehicles. The data below shows the speeds of the first 9 cars that pass.

46   56   45   44   45   61   55   53   39

What is the standard deviation, to the nearest tenth, based on the posted speed limit, 45 mph?

johnweldon1993 · Answer

Well we need to first find the mean of this data

Then we compare it to each of the individual speeds (subtract the mean from them)

Square all those results

Then add all those together and divide by 9 (find the average)

This will give you the variance of the data...to get the standard deviation, take the square root of this number