AP Statistics Chapter

Above is a dot plot of voter turnout (as a percentage of voting-age population) for the 50 states—plus the District of Columbia—in a recent presidential election. Which of the following best describes this distribution?

• Skewed slightly left, centered at about 62%, with a range of 24 percentage points.

• Roughly symmetric, centered at about 60%, with a range of 30 percentage points.

• Skewed slightly right, centered at about 62%, with a range of 24 percentage points.

Independently selected groups of middle-school children were given a poem to memorize. After a certain period of time, they were asked to recall as much of the poem as they could. A back-to-back stem plot of the distribution of the number of words that each group of children could correctly remember is displayed. Which of the following statements about these data is true?

• There are more students in Group 1 than in Group 2.

• In general, children in Group 2 were able to recall more words than children in Group 1.

• The third quartile of the Group 1 distribution is larger than the maximum value of the Group 2 distribution (that is, 25% of the Group 1 values are larger than any Group 2 value).

Which of the distributions displayed in the dot plots has the highest standard deviation?

• Distribution A

• Distribution B

• Distribution C

The stem-and-leaf diagram gives the distribution of the ages in years of 20 participants at a family reunion. Which of the following statements about the distribution is correct?

• The mean is larger than the median.

• The distribution is strongly skewed to the left.

• It makes the most sense to use the mean and standard deviation as a numerical summary of the center and spread of this distribution.

Is this a probability distribution?

• No, the sum of p(x) does not equal 1.

• Yes, all p(x) are between 0 and 1.

• No, all p(x) are not between 0 and 1.

• Yes, the sum p(x) is 1.

• A

• B

• C

• D

• E

Is this a probability distribution?

• No

• Yes

The owner of a convenience store keeps track of how many customer buy lunch food during the “noon rush” each day for four days and calculates that the mean number of customers for those four days is 52. How many customers must come in on the fifth day to make the five-day mean 54?

• 54

• 60

• 62

According to the 1.5 x IQR rule, how many outliers are there in the data set 72, 110, 114, 115, 118, 123, 144, 156?

• None

• One

• Two

The histogram shows the typical travel time to school (self-reported) for 50 high school students. Which of the following statements is true about the mean and median of this distribution?

• Mean > Median

• Mean < Median

• Mean = Median