2/26 Variance, Standard Deviation and Normal Distribution Pract

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

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

• 1

• 2

• 3

• 4

Any normal probability distribution can be converted to the standard normal probability distribution by the following formula

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.

Which is NOT true about the standard normal distribution?

• It is bell-shaped.
• It is unimodal.
• The mean is 0 and the standard deviation is 1.
• It is asymmetrical.

If I tell you that you scored at the 55th percentile on your final exam, you would know:

• 55% of the class scored the same or worse than you did

• You earned a 55% on the exam

• You failed the exam

• 45% of the class scored worse than you did

What percent of people within 1 standard deviation of the mean?

• 99.7

• 34

• 68

• 95

What percent of people within 2 standard deviations of the mean?

• 99.7

• 34

• 68

• 95

What percent of people within 3 standard deviations of the mean?

• 99.7

• 34

• 68

• 95

How is the z-score calculated?

• By adding the mean to the data value

• By subtracting the mean from the data value and dividing by the standard deviation

• By multiplying the mean with the data value

• By dividing the data value by the standard deviation