# Question: A radar unit is used to measure the speed of

A radar unit is used to measure the speed of auto-mobiles on an expressway during rush-hour traffic. The speeds of individual automobiles are normally distributed with a mean of 62 mph.

a. Find the standard deviation of all speeds if 3% of the automobiles travel faster than 72 mph.

b. Using the standard deviation found in part a, find the percentage of these cars that are traveling less than 55 mph.

c. Using the standard deviation found in part a, find the 95th percentile for the variable “speed.”

a. Find the standard deviation of all speeds if 3% of the automobiles travel faster than 72 mph.

b. Using the standard deviation found in part a, find the percentage of these cars that are traveling less than 55 mph.

c. Using the standard deviation found in part a, find the 95th percentile for the variable “speed.”

**View Solution:**## Answer to relevant Questions

The weights of ripe watermelons grown at Mr. Smith’s farm are normally distributed with a standard deviation of 2.8 lb. Find the mean weight of Mr. Smith’s ripe watermelons if only 3% weigh less than 15 lb. The diameter of each cork, as described in Applied Example 6.13, is measured in several places and an average diameter is reported for the cork. The average diameter has a normal distribution with a mean of 24.0 mm and ...Using the z(a) notation (identify the value of a used within the parentheses), name each of the standard normal variable z’s shown in the following diagrams Using Table 4B, find the z-scores that bound the middle 0.98 of the normal distribution. Verify the z-scores using Table 4A. Find the normal approximation for the binomial probability P(x = 6), where n = 12 and p = 0.6. Compare this to the value of P(x = 6) obtained from Table 2.Post your question