Normal Distribution and Z Scores

Find the z-score with 4-% of the observations falling below it.

• z=-0.25

• z=-0.33

• z=0.25

• z=0.33

IQ tests have a mean of 100 and SD of 16. Einstein's IQ was 160. What is the z-score of his IQ?

• 1.75

• 3.75

• 0.75

• 2.75

Pat and Tom took a test with mean 80 and SD 9. Pat scored a 76; Tom scored a 94. Find the percent of people between their scores.

• 68.78%

• 63.29%

• 65.14%

• 34.25%

Z-score of 2.5 on an IQ test is considered a genius (mean=100, SD=16). What score makes someone a genius? Hint: SOLVE for X

• 89.2

• 130

• 99.38

• 140

Test has a mean of 40, standard deviation of 10. What is the percent of people with a score below 37?

• 52.97%

• 31.53%

• 48.99%

• 38.21%

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%

Mean=65 mph, SD=2 mph. What speed is the 95th percentile?

• 95 mph

• 68 mph

• 73 mph

• 69 mph

Which of the following is a formula that describes calculating a z-score?

• Z = (score - mean) / stand. devation

• Z = (mean - score) / stand. dev.

• Z = score/stand. dev/ mean

• Z = dragonball

The sign of the z-score indicates whether the location is above(positive) or below(negative) the mean.

• True

• False

Find the Z-score.

Mean = 22

Standard Deviation: 3.1

x = 29

• 2.26

• 16.45

• -2.26

• 1.26