The National Highway Traffic Safety Administration analyzes the crash test data for new cars. One variable measured is the severity of the injury due to a collision. The higher the severity, the higher the points assigned. Assume that the injury rating is normally distributed with a mean (ì) of 605 points and a standard deviation (ó) of 185 points. One of the crash-test cars is randomly selected from the data and its rating is observed.

Question

The National Highway Traffic Safety Administration analyzes the crash test data for new cars. One variable measured is the severity of the injury due to a collision. The higher the severity, the higher the points assigned. Assume that the injury rating is normally distributed with a mean (ì) of 605 points and a standard deviation (ó) of 185 points. One of the crash-test cars is randomly selected from the data and its rating is observed.

Find the probability that the rating will fall between 500 and 700 points.

Answer 1

Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability from the mean for both Z scores. Add the two probabilities.