Making Inference from Random Samples

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.

Ana wants to know the average student’s opinion of the tardy policy at her school. Which group of students should she survey in order to achieve the most accurate results?

• Thirty randomly selected students from her school

• Thirty students who are rarely tardy

• thirty of her friends

True or False: Random samples can represent the population

• True

• False

Making a conclusion by interpreting data is called making a(n) ________________________.

• Inference

• population

• random sample

• sample

• valid inference

A town has 35,000 registered voters. A random sample of 500 voters finds that 125 are in favor of a new dog park. How many are likely to vote for the dog park?

• 25

• 125

• 2,625

• 8,750

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.

Zoie completes a report by asking 70 students across campus. She found that 48% of CIAA students do not wash their hands after using the bathroom. What is the population of her survey?

• the bathroom

• CIAA students

• 48% of students

Biased or Random?

Audi wants to find out how students get to school at Menifee Elementary so she places the names of all students into a fish bowl and pulls out 50 so she can survey them.

• Biased

• Random