Question

PLEASE HELP!!!!

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?

The tenth car traveling on this road breaks down and is being pushed by its owners as it passes the speed monitor. A speed of 1.5 mph is recorded. The measure of central tendency most affected by this tenth speed is what?

Answer 1

What is the new standard deviation, to the nearest tenth, after the tenth speed is recorded?

Answer 2

When I was learning how to do standard deviation this helped me out a lot:
http://www.mathsisfun.com/data/standard-deviation.html
Hope this helps!

Answer 3

the first thing you need to do is work out the mean of the 9 recorded speeds
then you subtract this mean from each of the speeds and square each one
and total these squares.
them divide by the number of speeds (9)finally, take the square root of the reselt