Z-Scores

For a certain type of computer, the length of time between charges of the battery is normally distributed with a mean of 50 hours and a standard deviation of 15 hours. John owns one of these computers and wants to know the probability that the length of time will be between 50 and 70 hours.

• 0.9082

• 0.8989

• 0.5000

• 0.4087

In a city, it is estimated that the maximum temperature for the thirty days of June is normally distributed with a mean of 23 degrees and a standard deviation of 5 degrees. Calculate the number of days in this month in which it is expected to reach a maximum temperature between 21 and 27 degrees.

• 4 days

• 8 days

• 10 days

• 13 days

For Mrs. V: mean = 55 and standard deviation = 19

For Mr. T: mean = 33 and standard deviation = 10.5

Mary Beth is very proud of the score of 80 that she earned in Mrs. V's class. Albert is equally proud of the score of 42 he earned in Mr. T's class. Who has the better score?

• Mary Beth

• Albert

For Mrs. V: mean = 55 and standard deviation = 19

For Mr. T: mean = 33 and standard deviation = 10.5

What percent of students scored 80 or higher in Mrs. V's class? Round your answer to the nearest tenth, do not put a percent sign.

For Mrs. V: mean = 55 and standard deviation = 19

For Mr. T: mean = 33 and standard deviation = 10.5

What percent of students scored 42 or higher in Mr. T's class? Round your answer to the nearest tenth, do not put the percent sign.

At a company, the data set containing the ages of applicants for a particular job was 30 years old, and the standard deviation of the data set was 3.5 years. Which is closest to the percent of applicants that were 21 years old or younger?

• 0.5%

• 2.0%

• 2.57%

• 9.0%

A normally distributed data set of 500 values has a mean of 35 and a standard deviation of 7. Which is closest to the probability that a value in the data set will fall between 42 and 46? (The answer is given as a decimal and not a percent).

• 0.04

• 0.10

• 10

• 50

A normally distributed data set of 600 values has a mean of 18.5 and a standard deviation of 3.25.

What is the approximate number of values in the data set expected to be 22 or greater? Round to the nearest whole number AT THE END!

A normally distributed data set of 600 values has a mean of 18.5 and a standard deviation of 3.25.

What is the approximate numbers of values in the data set expected to be 16 or fewer? Round to the nearest whole number AT THE END!

A normally distributed data set of 600 values has a mean of 18.5 and a standard deviation of 3.25.

How many values lie between 21 and 27? Round to the nearest whole number AT THE END!