AP Statistics Cumulative Review

Approximately 52 percent of all recent births were boys. In a simple random sample of 100 recent births, 49 were boys and 51 were girls. The most likely explanation for the difference between the observed results and the expected results in this case is

• bias

• variability due to sampling

• non-sampling error

• confounding

Tags

CCSS.HSS.IC.B.3

Suppose there is a correlation of r = 0.9 between number of hours per day students study and GPAs. Which of the following is a reasonable conclusion?

• 90% of students who study receive high grades.

• 90% of students who receive high grades study a lot.

• 90% of the variation in GPAs can be explained by variation in number of study hours.

• 10% of the variation in GPAs cannot be explained by variation in number of study hours per day.

• 81% of the variation in GPAs can be explained by variation in number of study hours per day.

Tags

CCSS.HSS.ID.B.6A

Which of the following statements about the correlation coefficient are true?

I. The correlation coefficient and the slope of the regression line may have opposite signs.

II. A correlation of 1 indicates a perfect cause-and-effect relationship between the variables.

III. Correlations of +.87 and −.87 indicate the same degree of clustering around the regression line.

• I only

• II only

• III only

• I and II

• I, II, and III

Tags

CCSS.HSS.ID.B.6B

In which of the following situations would it be most difficult to use a census?

• To determine what proportion of licensed bicycles on a university campus have lights

• To determine what proportion of students in a high school support wearing uniforms

• To determine what proportion of registered students enrolled in a college are employed more than 20 hours each week

• To determine what proportion of single-family dwellings in a small town have two-car garages

• To determine what proportion of fish in Lake Michigan are bass

Tags

CCSS.7.SP.A.1

CCSS.HSS.IC.A.1

One advantage of using a stem-and-leaf plot rather than a histogram is that the stem-and-leaf plot

• shows the shape of the distribution more easily than the histogram.

• changes easily from frequency to relative frequency.

• shows all of the data on the graph.

• presents the percentage distribution of the data.

• shows the mean on the graph.

A professor scaled (curved) the scores on an exam by multiplying the student’s raw score by 1.2, then adding 15 points. If the mean and standard deviation of the scores before the curve were 51 and 5, respectively, then the mean and standard deviation of the scaled scores are respectively:

• 76.2 and 21

• 76.2 and 6

• 76.2 and 5

• 61 and 6

• cannot be determined without knowing if the scores are normally distributed

A two-sided hypothesis test for a population mean is significant at the 1% level of significance. Which of the following is necessarily true?

• The 99% confidence interval of the mean contains 0.

• The 99% confidence interval of the mean does not contain 0.

• The 99% confidence interval of the mean contains the hypothesized mean.

• The 99% confidence interval of the mean does not contain the hypothesized mean.

• The 99% confidence interval is not useful here.

As part of survey of college students a researcher is interested in the variable class standing. She records a 1 if the student is a freshman, a 2 if the student is a sophomore, a 3 if the student is a junior, and a 4 if the student is a senior. The variable class standing is

• incremental

• numerical

• Categorical

• quantitatively categorical.

• all of the above.

There are three children in a room, ages three, four, and five. If a four-year-old child enters the room, the

• mean age will stay the same but the variance will increase

• mean age will increase, but the variance will stay the same

• mean age and variance will stay the same

• mean age and variance will increase

• mean age will stay the same but the variance will decrease

A study found that 63 of 211 randomly selected men and 130 out of 651 randomly selected women prefer cats to dogs. You want to test the hypothesis that women like cats more. Choose the correct hypotheses and pooled pˆ .

• H0: pM = pF; HA: pM < pF; p ˆ = .224

• H0: pM = pF; HA: pM > pF; p ˆ = .249

• H0: pM = pF; HA: pM < pF; p ˆ = .249

• H0: pM = pF; HA: pM > pF; p ˆ = .224

• H0: pM < pF; HA: pM > pF; p ˆ = .224