Statistics Review

A market researcher asked a group of men and women to choose their favorite color design from a sample of advertisements. The results are shown in the following table.

Which of the following statements is not supported by the table?

• More men than women chose the color design red with black.

• More women than men chose the color design yellow with black.

• For men, the number who chose a design with black was greater than the number who chose a design with blue.

• The color design chosen by the most people was green with blue.

• The total number of men surveyed by the market researcher was equal to the total number of women surveyed by the market researcher.

The distribution of the number of transactions per day at a certain automated teller machine (ATM)

(ATM) is approximately normal with a mean of 80 transactions and a standard deviation of 10 transactions. Which of the following represents the parameters of the distribution?

The boxplots above summarize two data sets, A and B. Which of the following must be true?

I.Set A contains more data than Set B.

II.The box of Set A contains more data than the box of Set B.

III. The data in Set A have a larger range than the data in Set B.

• I only

• III only

• I and II only

• II and III only

• I, II, and III

The histogram below displays the frequencies of waiting times, in minutes, for 175 patients in a dentist's office.

Which of the following could be the median of the waiting times, in minutes?

• 2.50

• 7.25

• 12.25

• 15.00

• 17.50

For a sample of 42 rabbits, the mean weight is 5 pounds and the standard deviation of weights is 3 pounds. Which of the following is most likely true about the weights for the rabbits in this sample?

• The distribution of weights is approximately normal because the sample size is 42, and therefore the central limit theorem applies

• The distribution of weights is approximately normal because the standard deviation is less than the mean.

• The distribution of weights is skewed to the right because the least possible weight is within 2 standard deviations of the mean.

• The distribution of weights is skewed to the left because the least possible weight is within 2 standard deviations of the mean.

• The distribution of weights has a median that is greater than the mean.

A survey of 57 students was conducted to determine whether or not they held jobs outside of school. The two-way table above shows the number of students by employment status (job, no job), and class (juniors, seniors). Which of the following best describes the relationship between employment status and class?

• There appears to be no association, since the same number of juniors and seniors have jobs.

• There appears to be no association, since close to half of the students have jobs.

• There appears to be an association, since there are more seniors than juniors in the survey.

• There appears to be an association, since the proportion of juniors having jobs is much larger than the proportion of seniors having jobs.

• A measure of association cannot be determined from these data.

A restaurant manager collected data on the number of customers in a party in the restaurant and the time elapsed until the party left the restaurant. The manager computed a correlation of 0.78 between the two variables. What information does the correlation provide about the relationship between the number of customers in a party at the restaurant and the time elapsed until the party left the restaurant?

• The relationship is linear because the correlation is positive.

• The relationship is not linear because the correlation is positive.

• The parties with a larger number of customers are associated with the longer times elapsed until the party left the restaurant.

• The parties with a larger number of customers are associated with the shorter times elapsed until the party left the restaurant.

• There is no relationship between the number of customers in a party at a table in the restaurant and the time required until the party left the restaurant.

A family would like to build a linear regression equation to predict the amount of grain harvested per acre of land on their farm. They subdivide their land into several smaller plots of land for testing and would like to select an explanatory variable they can control. Which of the following is an appropriate explanatory variable that the family could use to create a linear regression equation?

• The total amount of rainfall recorded at their farm

• The type of crop planted in the plot the previous year

• The average daily temperature at their farm

• The variety of grain planted in the plot

• The amount of fertilizer applied to each plot of land

A researcher collected data on the age, in years, and the growth of sea turtles. The following graph is a residual plot of the regression of growth versus age.

Does the residual plot support the appropriateness of a linear model?

• Yes, because there is a clear pattern displayed in the residual plot

• Yes, because about half the residuals are positive and the other half are negative.

• Yes, because as age increases, the residuals increase.

• No, because the points appear to be randomly distributed.

• No, because the graph displays a U

  -shaped pattern.

A researcher studying a specific type of tree creates a least-squares regression line for relating the height and the diameter, both in meters, of a fully grown tree. The results are shown in the following computer output.

Which of the following values represents the predicted change in the height of the tree for each one-meter increase in the diameter of the tree?

• 30

• 5

• 4

• 2.5