Unit 2: Describing distributions & density curves

A researcher is interested in how much annual snowfall is typical in the United States. She takes a random sample of 9 cities in the U.S. and records the annual rainfall, in inches. Find the median annual snowfall for these cities.

• 40.5

• 42.3

• 39.2

• 41.5

The mean of years a car lasts is 15 years. The standard deviation is 3 years. Then, 68% of all cars will last between ___ and ____ years. 

• 3 and 15 

• 12 and 18

• 9 and 15

• 12 and 21

The average pairs of shoes owned is 10 with a standard deviation of 2. If pairs of shoes is normally distributed, determine the z- score of pairs of shoes less than 14.

• -2

• -1

• 1

• 2

The heights of adult males are approximately normally distributed with a mean of 70 inches and a standard deviation of 3 inches. What height corresponds to the 16th percentile? Use Empirical Rule and solve.

• The 16th percentile is 5 standard deviations above the mean

• The 16th percentile is 1 standard deviation below the mean

• The 16th percentile is -1 standard deviation above the mean

• None of the above

The times someone goes to a movie theater in a year is normally distributed with a mean of 12 visits and a standard deviation of 3 visits. About what percent of the visits in a year  are between 12 and 15 visits?

• 68%

• 34%

• 16%

• 2.5%

The standard deviation of the annual snowfall for these 9 cities is 15.52 inches. The mean of the annual snowfall is 34.9. Interpret this value.

• The typical annual snowfall varies by 34.9 from the mean 15.5.

• The typical annual snowfall varies by 15.5 from the median 34.9.

• None of the above

• The typical annual snowfall varies by 15.5 from the mean 34.9

The mean number of chocolate chips in a cookie is 21 chocolates . The standard deviation is 4 chocolates. Then 16% of all cookies will have between _____ and ____ chocolate chips.

• 13 and 21

• 9 and 17

• 14 and 29

• 21 and 25

According to research, the state of Washington was at the 82nd percentile for Pre-K to 12th athletic training rating and was at the 2nd percentile for higher athletic performance rating. Explain what these values mean.

• Washington had a higher Pre-K to 12th grade athletic training rating than 82% of the states and had a higher athletic performance over 2% of the states.

• Washington had a higher Pre-K to 12th grade athletic performance over 82% of the states and an athletic training rating over 2% of the states.

• Washington had a lower Pre-K to 12th grade athletic training rating than 82% of the states and had a lower athletic performance over 2% of the states

• None of the above

The average hair length for a teenage girl is 15 inches with a standard deviation of 3 inches. If hair length is normally distributed, determine the z-score of a teenage girl more than 18 inches

• -2

• -1

• 1

• 2

The state of New York has a standardized score of 0.267, a standard deviation of 32.844, and a mean of 39.24. How many public colleges does New York have?

• 48

• 70

• 64

• 32