Unit 1-4 Review MCQ

Which of the following is a true statement?

• 1. Stemplots are useful for both quantitative and categorical data sets.

• 1. Stemplots are equally useful for small and very large data sets.

• 1. Stemplots can show symmetry, gaps, clusters, and outliers.

• 1. Stemplots may or may not show individual values.

• 1. Stems may be skipped if there is no data value for a particular stem.

Allan famously quipped that when he moved from Pennsylvania to California, the average IQ dropped in both states. What would have had to been true for this to happen?

• 1. Allan's IQ was greater than the average IQ in both Pennsylvania and California.

• 1. Allan's IQ was greater than the average IQ in Pennsylvania and less than the average IQ in California.

• 1. Allan's IQ was less than the average IQ in Pennsylvania and greater than the average IQ in California.

• 1. Allan's IQ was less than the average IQ in both Pennsylvania and California.

• 1. There is no way for Allan's statement to be true.

The stemplot below shows ages of CEOs of a select group of corporations.

Which of the following is not a correct statement about this distribution?

• 1. The distribution is roughly bell-shaped.

• 1. The distribution is skewed left and right.

• 1. The center is around 60.

• 1. The spread is from 22 to 90.

• 1. There are no outliers.

Students in an algebra class were timed in seconds while solving a series of mathematical brainteasers. One student’s time had a standardized score of z = 2.40. If the times are all changed to minutes, what will then be the student’s standardized score?

• 1. z = 0.04

• 1. z = 0.4

• 1. z = 1.80

• 1. z = 2.40

• 1. The new standardized score cannot be determined without knowing the class mean.

If quartiles Q₁ = 20 and Q₃ = 30, which of the following must be true?

1. I. The median is 25.

   1. II. The mean is between 20 and 30.

2. III. The standard deviation is at most 10.

• 1. I only

• 1. II only

• 1. III only

• 1. All must be true.

• 1. None must be true.

Below is a boxplot of CO₂ levels (in grams per kilometer) for a sampling of year 2018 vehicles.

Suppose follow-up testing determines that the low outlier should be 10 grams per kilometer less and the two high outliers should each be 5 grams per kilometer greater. What effect, if any, will these changes have on the mean and median CO₂ levels?

• 1. Both the mean and median will be unchanged.

• 1. The median will be unchanged, but the mean will increase.

• 1. The median will be unchanged, but the mean will decrease.

• 1. The mean will be unchanged, but the median will increase.

• 1. Both the mean and median will change.

A teacher is teaching two AP Statistics classes. On the final exam, the 20 students in the first class averaged 92, while the 25 students in the second class averaged only 83. If the teacher combines the classes, what will the average final exam score be?

• 87

• 87.5

• 88

• None of the above

• 1. More information is needed to make this calculation.

Suppose the average score on a national test is 500 with a standard deviation of 100. If each score is increased by 25%, what are the new mean and standard deviation, respectively?

• 1. 500 and 100

• 1. 525 and 100

• 1. 625 and 100

• 1. 625 and 105

• 1. 625 and 125

The following dotplot shows the speeds (in mph) of 100 fastballs thrown by a major league pitcher.

Which of the following is the best estimate of the standard deviation of these speeds?

• 1. 0.5 mph

• 1. 1.1 mph

• 1. 1.6 mph

• 1. 2.2 mph

• 1. 6.0 mph

Consider the following two normal curves.

Which has the smaller mean, and which has the smaller standard deviation?

• 1. Smaller mean, a; smaller standard deviation, a

• 1. Smaller mean, a; smaller standard deviation, b

• 1. Smaller mean, b; smaller standard deviation, a

• 1. Smaller mean, b; smaller standard deviation, b

• 1. Smaller mean, a; same standard deviation