Use the following information for following questions . A police radar gun is used to measure the speeds of cars on a
highway. The speeds of cars are normally distributed with a mean of 55 mi/hr and a standard deviation of 5
mi/hr.
-Roughly what percentage of cars are driving less than 45 mi/hr? (Round to the nearest tenth of a percent)
A)5.0%
B)95.0%
C)18.0%
D)2.5%.

Question

Quizplus · Accepted Answer

Using the properties of the normal distribution, a speed of 45 mi/hr is 2 standard deviations below the mean (55 - 2*5 = 45). Approximately 2.5% of the data falls below 2 standard deviations from the mean in a normal distribution.

Use the Following Information for Following Questions