Topic 11 Review

The mean, median and standard deviation of four data sets are shown. Which statement about the data sets is correct?

• Only data set A is positively skewed.

• Only data set C is positively skewed.

• Data set B and data set D are both positively skewed.

• Data set C and data set D are both positively skewed.

A certain make and model of a car gets an average highway gas mileage of 34.8 mpg with a standard deviation of 5.2 miles per gallon. If the gas mileages are normally distributed, approximately what percentage of cars of this make and model get a highway gas mileage between 29.6 and 40 mpg?

• 32%

• 34%

• 68%

• 95%

Use the information given to answer the question. Judy has an average math test score of 88.5 with a standard deviation of 4.2. Her scores follow a normal distribution. What is the range that includes 68% of Judy’s scores?

• 80.1 to 96.9

• 84.3 to 92.7

• 86.4 to 90.6

• 88.5 to 99

The test scores of students on a science test are normally distributed with an average score of 78 and a standard deviation of 4. Which statement is true?

• About 16% of the students scored 74 or below.

• About 32% of the students scored 82 or above.

• About 50% of the students scored 74 or above.

• About 68% of the students scored 82 or below.

A teacher finds that the test scores for a class have a mean of 75 with a standard deviation of 10. If the data follow a normal distribution, what is the approximate probability that a randomly selected test has a score less than 85?

• 16%

• 32%

• 68%

• 84%

In a region of the Caribbean Sea, daily water temperatures are normally distributed with a mean of 77.9 and a standard deviation of 2.4. What is the probability a randomly selected daily temperature is less than 73.1?

• A 97.5%

• B 95%

• C 5%

• D 2.5%

The scores of a statistics mid-term exam are normally distributed with a mean of 81 and a standard deviation of 6.3. Approximately what percentage of the students score less than a 93?

• A 97.32%

• B 97.13%

• C 2.87%

• D 2.68%

The weights of one-year old babies at a pediatric clinic are normally distributed with a mean of 9.5 kilograms and a standard deviation of 1.1 kilograms. Approximately what percentage of one-year old babies weigh more than 8.95 kilograms?

• A 29.12%

• B 30.85%

• C 69.15%

• D 70.88%

Dallas wants to know his height relative to the other football players on the team. The team’s mean height is 73 inches with a standard deviation of 4 inches. Dallas is 70 inches tall. What is Dallas’s z-score?

• -1.1

• -0.75

• 0.75

• 1.1

Brooke earned a z-score of 0.43 on a recent English test. Carol earned a z-score of 1.88 on the same test. Based on this information, which statement is true?

• Carol earned the highest score in the class on the test.

• Brooke’s score was closer to the average test score.

• Brooke did relatively better than Carol on the test.

• The two students both earned a B on the test.