Normal Distribution

Find the z-score for 75 given a mean of 60 and a standard deviation of 6.

• -2.5

• 2.5

• -1.15

• 1.15

Find the z-score for 48 given a mean of 50 and a standard deviation of 5.

• 2.5

• -2.5

• -0.4

• 0.4

What percentage of scores falls within 3 standard deviations of the mean?

• 68%

• 34%

• 99.7%

• 95%

A test has a mean of 40 and a standard deviation of 10. What is the percent of people that scored between 30 and 40?

• 68%

• 34%

• 13.6%

• 100%

Students pass a test if they score 50% or more.

The marks of a large number of students were sampled and the mean and standard deviation were calculated as 42% and 8% respectively.

Assuming this data is normally distributed, what percentage of students pass the test? in percentage...

• 5

• 16

• 24

• 32

The 40 yards sprint times for a soccer team are found to be normally distributed with a mean of 5.2 seconds and a standard deviation of 0.3 seconds.  What is the z-score for a player who runs a time of 5.6 seconds?

• -1.33
• 1.33
• 0.88
• 1.02

Between what two standard deviations of a normal distribution contain 68% of the data?

• one below and one above
• two below and two above
• two below and zero
• zero and two above

What is the the total area under the standard normal distribution curve?

• 100
• 25
• .5
• 1

The z-score represents.....

• the amount of standard deviations a data value is above or below the mean.
• the percentile the data value is above or below the mean.
• the amount of standard deviations a data value is above or below the median.
• the percent the data value is above or below the mean.

The shelf life of a particular dairy product is normally distributed with a mean of 12 days and a standard deviation of 3 days.

About what percent of the products last between 12 and 15 days?

• 68%
• 34%
• 16%
• 2.5%