Statistics Review

If this is the graph of data normally distributed with a mean of 30 and a standard deviation of 5, what label (number) is written at the blue circle?

• 20

• 15

• 40

• 30

Use the following information and the Normal Distribution Curve to estimate the answer.

The ages of golfers are normally distributed, with a mean of 38 and a standard deviation of 4.

Find the percentage of golfers that are between 30 and 46 years old.

• 68%

• 94%

• 95%

• 99.7%

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%

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

If there are a total of 20,000 units produced, about how many products last between 12 and 15 days?

• 18,000

• 6,800

• 3,200

• 680,000

A large number of packs of coffee were weighed and the mean and standard deviation were calculated as 255 g and 2.5 g respectively.

Assuming this data is normally distributed and there are 100,000 packages made, how many packs are underweight? (the package is supposed to weigh at least 250 grams)

• 2,500

• 3,500

• 4,000

• 97,500

Tags

CCSS.HSS.ID.A.4

Joanne's score on a test gives her a Z-score is -1.50. What does this mean?

• Joanne didn't take the test yet.

• Joanne's test score is 1.50 standard deviations below the average test score.

• Joanne did better than 1.50 times her peers.

• Joanne's test score, on average, was 1.5 points lower than the other test scores.

Adam's Z-score on a test is +2.50. What does this mean?

• Adam's score has a 2.5% chance of being better than any other randomly selected score.

• Adam's test score was better than 25% of his peers.

• He scored 2.5 standard deviations above the average.

• He did terrible.

Adam's Z-score on a test is +2.50. What is the percentile score and what does it mean?

• .8355, which means his test score is higher than 83.55% of other test takers in the group

• .9938, which means his test score is lower than 99.38% of other test takers in the group

• .9938, which means his test score is higher than 99.38% of other test takers in the group

• .995, which means his score is 99.5% higher than other test takers in the group

What is the Z-score for Tina if she got a 31 on the ACT, the mean was 23 and the SD was 4?

• +0.20

• +2.00

• -2.00

• -0.20

What does a z-score of 2 mean?

NOTE: There are multiple correct answers!

• That persons ACT score is HIGHER than 97.72% of other scores in the group.

• That persons ACT score is 2 standard deviations HIGHER than the average test score.

• That persons ACT score is 2 standard deviations LOWER than the average test score.

• That persons ACT score is HIGHER than 98.22% of other scores in the group.