Standard Deviation AP Statistics

Jorge's score on Exam 1 in his statistics class was at the 64th percentile of the scores for all students. His score falls

• between the minimum and the first quartile

• between the first quartile and the median

• between the median and the third quartile

• between the third quartile and the maximum

• at the mean score for all students

When Sam goes to a restaurant, he always tips the server $2 plus 10% of the cost of the meal. If Sam's distribution of meal costs has a mean of $9 and a standard deviation of $3, what are the mean and standard deviation of his tip distribution?

• $2.90, $0.30

• $2.90, $2.30

• $9.00, $3.00

• $11.00, $2.00

• $2.00, $0.90

Scores on the ACT college entrance exam follow a bell-shaped distribution with mean 21 and standard deviation 5. Wayne's standardized score on the ACT was -0.6. What was Wayne's actual ACT score?

• 3

• 13

• 16

• 18

• 24

George's average bowling score is 180; he bowls in a league where the average for all bowlers is 150 and the standard deviation is 20. Bill's average bowling score is 190; he bowls in a league where the average is 160 and the standard deviation is 15. Who ranks higher in his own league? Bill or George?

• Bill, because his 190 is higher than George's 180.

• Bill, because his standardized score is higher than George's.

• Bill and George have the same rank in their leagues, because both are 30 pins above the mean.

• George, because his standardized score is higher than Bill's.

• George, because the standard deviation of bowling scores is higher in his league.

If a dot plot of data is skewed right, what shape will the dot plot be if we subtract 10 from each of the data points?

• skewed left

• skewed right

• symmetrical

• we would need more information

Sandra scored a 65% on her first Physics exam. The class mean was a 62% with a standard deviation of 8%. Calculate Sandra's z-score.

• 3

• -0.375

• 0.375

• -3

Wyatt Stanley's height is at a z-score of -.75. What does this mean?

• He is .75 inches below the mean of all children.

• He is .75 standard deviations below the mean of other children his age.

• He is .75 standard deviations below the mean of all children.

• He is .75 inches below the mean of other children his age.

What is the shape of this distribution?

• Skewed left

• Skewed right

• Uniform

• Symmetrical

If we took a distribution of points and added 20 to each point, what would change?

• Shape

• Mean

• Range

• Standard Deviation

A symmetrical distribution has a mean of 6 and a standard deviation of 2. What would be true about this distribution if we multiplied each data point by 2?

• Symmetrical, mean = 6, standard deviation =4

• Symmetrical, mean = 12, standard deviation =4

• Symmetrical, mean = 12, standard deviation =2

• Symmetrical, mean = 6, standard deviation =2