unit 2: mcq part a

For which of the following scatterplots is the correlation between x and y closest to −1 ?

(e) the negative linear function that goes from the upper left corner to the lower right.

The following table shows the responses of 45 students from two different classes who were asked which of five amusement rides at a school fair was their favorite. For which ride was the proportion of the class who chose it as their favorite the same for both classes?

Boat Ride

A certain cell phone plan charges a fee of $1 for each international call made plus $0.02 for each second of talk time for the international call. A business owner tracked the time and cost for each of the calls made by the employees when they traveled internationally for business. What is the appropriate value of the correlation between time and cost for the international calls?

The appropriate value is 1 because there is a perfect linear relationship between the time of the call and how much it costs.

The following scatterplot displays the data collected on the mass, in grams, and the age, in days, for a sample of chameleon eggs. Which of the following is the best description of the relationship between the mass and the age of the chameleon eggs?

The association is positive and nonlinear.

The following bar chart shows the number of different types of animals at two county fairs. Fair X had a total of 645 animals, and fair Y had a total of 590 animals. Which of the following statements is supported by the bar chart?

The percentage of all animals at fair Y that are goats is greater than the percentage of all animals at fair X that are goats.

The following two-way table shows the responses from a group of people, categorized by age-group, when asked about their favorite types of vacations. Which of the following statements is not supported by the table?

The percentage of people that chose relaxation was equal for each age-group.

A certain middle school opens at 7 A.M., and classes begin at 8 A.M. A sociologist gathered data on the number of minutes after 7 A.M. that a student arrives at school and the number of friends the student has on social media. The correlation between the two variables indicated a strong negative relationship. Which of the following is an appropriate interpretation of the correlation?

As the number of minutes of arriving after 7 A.M. increases, the number of friends on social media tends to decrease.

Biologists conducted a study to investigate the flying velocity of mosquitoes both before and after feeding. The following scatterplot shows the velocity after feeding, in centimeters per second, and the proportional increase in weight after feeding relative to the weight before feeding. For example, 0.5 indicates a 50 percent weight gain after feeding. One point on the graph is labeled M. What is unusual about point M?

It represents a mosquito that flew very fast after feeding relative to all other mosquitoes.

The following table shows the number of registered voters in three different regions and the political party in which they are registered. Which of the following statements is supported by the table?

The region with the greatest proportion of voters who are registered Republican is region B.

A teacher collected information from a class of 25 students about the time, in hours, they spent studying the previous week and the time, in hours, they spent on the Internet the previous week. The value of the correlation coefficient between hours spent studying and hours spent on the Internet was −0.72. If the teacher changes the units of each variable from hours to minutes, what will be the value of the correlation coefficient between minutes studying and minutes spent on the Internet?

-0.72

A food truck owner recorded the temperature at noon, in degrees Fahrenheit, and the number of bowls of soup sold during the lunch hour for a random sample of 5 days. The data are shown in the following table. The mean temperature of the sample is 62 degrees Fahrenheit, and the mean number sold is 14. What is the correlation between the temperature and the number sold?

0.85

The following table shows data collected from a random sample of 2,500 people who recently went on a vacation, who indicated their favorite part of their vacation. Based on the table, what proportion of the people selected gave a response other than shopping as the favorite part of their vacation?

1,925/2,500

The scatterplot below displays the relationship between the percent change in the population of wolves and the moose density, in number of moose per square kilometer, over a 19-year period in a certain region. Notice that the association is negative, and that the points seem to be more spread out at higher moose densities. Suppose the variables on the scatterplot were reversed, so that moose density was the response variable on the vertical axis, and percent change in wolf population was the explanatory variable on the horizontal axis. Which of the following would be true?

The direction and strength of the association would not change.

A recent survey of wheat growers focused on the characteristics of wheat farmers and their willingness to participate in agricultural research. One of the variables of interest in the survey was the age of the farmer. The following bar chart shows the responses of the farmers, classified by age-group, regarding their willingness to participate. Which of the following statements is supported by the bar chart?

There appears to be a negative association between the age of the farmer and willingness to participate.

The following table shows data collected from a sample consisting of children and adults, who indicated their favorite type of amusement park rides. What proportion of the people indicated that water rides were their favorite type of ride?

600/2,000

A random sample of 2,500 people was selected, and the people were asked to give their favorite season. Their responses, along with their age group, are summarized in the two-way table below. Among those whose favorite season is spring, what proportion are adults?

225/475

Jacques, an artisan cheese maker, collects data on every step of the cheese-making process for each batch he makes. Jacques noticed that the daily high temperature in his shop on the day he made a batch of cheese was related to the pH of the cheese the next morning. He computed the correlation between the daily high temperature and the pH of the cheese to be −0.64. What information does the correlation provide about the relationship between the daily high temperature and the pH of the cheese?

The morning pH of the cheese tends to be higher when the daily high temperature in the shop is cooler, compared to when the daily high temperature is warmer.

A recent study investigated whether renowned violinists were able to classify the age of a violin. In the study, violins constructed before 1900 and violins constructed after 2010 were used. The violinists played each violin and were asked to classify the violin as old (constructed before 1900) or new (constructed after 2010). The responses are shown in the following table. Which of the following statements is supported by the results in the table?

The proportion of all correctly classified violins that are old is equal to the proportion of all new violins that are incorrectly classified.