Question

-Applications using z-scores-

(Note: draw the bell shape curve and convert data values to z-score)

A radar unit is used to measure speeds of cars on a motorway. The speeds are normally distributed with a mean of 90 km/hr and a standard deviation of 10 km/hr. What is the probability that a car picked at random is travelling at more than 100 km/hr?

Answer 1

Answer: 16%

step explanation:

100 m/hr is ONE S.D. (10) above 90

z - score = .8413 (Form Z-score chart)

means 84 % of cars are travelling less than 100 m/hr

~ 16% are traveling 100 or more