Unit 7 Statistics Test Review

Use the distributions to answer the following:

• A. The mean of set A is less than the mean of set B, and the standard deviations are the same.

• A. The standard deviation of set A is greater than the standard deviation of set B, and their means are the same.

• A. The mean of set A is greater than the mean of set B, and the standard deviations are the same.

• A. The standard deviation of set A is less than the standard deviation of set B, and their means are the same.

A store sells cheese in small, medium and large size packages. The small packages have a mean weight of 2 pounds and a standard deviation of 0.5 pound. If the weights for the small packages of cheese are approximately normally distributed, about 95% of the data falls between which two values?

• 1.5 and 2.5

• 1 and 1.5

• 1 and 3

• 2 and 3

The time it takes to complete a test is normally distributed with a mean of 45 minutes and a standard deviation of 12 minutes. If Nick took an hour and 8 minutes to complete the test, find his z-score to the nearest hundredth.

• 64.25

• -1.92

• 1.92

• 39.3

The 100-meter dash times in the girls track meet were normally distributed with a mean of 13 seconds and a standard deviation of 0.3 seconds.

What is the probability that a runner finished between 12.4 and 14 seconds?

• 68.2

• These are outliers

• 50%

• 97.6%

The 100-meter dash times in the girls track meet were normally distributed with a mean of 13 seconds and a standard deviation of 0.3 seconds.

What is the probability that it took a runner more than 13.5 seconds?

• 13.2%

• 95.25%

• 4.75%

• They would be an outlier.

The 100-meter dash times in the girls track meet were normally distributed with a mean of 13 seconds and a standard deviation of 0.3 seconds.

What is the probability that a runner finished in under 12.7 seconds?

• 15.87%

• 84.13%

• This runner is an outlier.

• 68.2%

A data set has a mean of 300 and a standard deviation of 40. What value would have a z-score of  $z=-2$  ?

• 298

• 296

• 220

• 380

A national achievement test is administered annually to 3rd graders. The test has a mean score of 100 and a standard deviation of 15. If Jane's z-score is 1.20, what was her score on the test?

• 82
• 88
• 100
• 118

Tina got a 31 on the ACT, the mean was 23 and the SD was 4. Paula got 1400 on the SAT, the mean was 1100 and the SD was 500. Who performed better?

• Tina's performance is farther away from the mean so she did better.

• Paula's score is closer to the mean so she did better.

• They both did the same.

• Can I take a nap now?

Which statement about Z-Scores is true?

• A positive z-score indicates the subject has a measurement less than the mean of the population.

• A subject with a z-score between 3 and -3 can be considered an outlier.

• A negative z-score indicates the subject has a measurement that is greater than the mean of the population.

• A z-score of zero indicates the subject has a measurement that is exactly the same as the mean of the population.