Sampling to Draw Inferences

The dot plots show the number of calls that two radio stations receive each day for a ten-day period. The two shows are shown at the same time. Which of the following inferences based on the median values is valid?

• The radio shows receive similar amounts of calls.

• Radio Show 1 generally receives more calls.

• Radio Show 2 generally receives more calls.

The food service manager conducted a random survey of students to determine their preference for new lunch menu items. Which of these inferences can be drawn from the manager’s data? Select all that apply.

• About twice as many students prefer salad bar as compared to pita sandwiches.

• Burritos are the most preferred item.

• About three-fourths of students prefer either salad bar or burritos.

• Twice as many students prefer pizza as compared to pita sandwiches.

• About half as many students prefer pita sandwiches as compared to burritos.

Margo wants to convince her father to change her curfew from 9 P.M. to 10 P.M. She gathers data on curfew times from a random sample of students at her middle school. Can Margo use these data to present a valid inference that will convince her father? Explain.

• Yes; Most students have a curfew of 10 P.M. or later.

• Yes; More students have a curfew of 9 P.M. than any other time.

• No; Most students have a curfew of 9 P.M. or earlier.

• No; More students have a curfew of 10 P.M. or 11 P.M. than 8 P.M.

Russell randomly surveys seventh-graders in his school and finds that 6 of 30 attend summer camp. If there are 200 seventh-graders in his school, about how many are expected to attend summer camp?

• 40

• 1,000

• 176

• There is not enough information to answer.

Group A and Group B were randomly sampled from the same population. What inference can you make?

• Group A has a higher median than Group B.

• Group B has a higher median than Group A.

Group A and Group B were randomly sampled from the same population. What inference can you make?

• Group A has higher overall variability because it has a larger range than Group B.

• Group A has a lower overall variability because it has a smaller range than Group B.

• Group B has a higher overall variability because it has a larger range than Group A.

• Group B has a lower overall variability because it has a smaller range than Group A.

How can sample data be used to form an estimate about the population?

• A proportion can be solved to relate the sample to the population.

• A proportion can be solved to relate the sample to the mean.

• A proportion can be solved to relate the sample to the median.

• You cannot make an estimation from sample data.