Making Statistics Inferences

Maria collects data from a random sample of 7th graders in her school and finds that 16 out of 20 7th graders participate in after-school activities. How many students should Maria expect to participate in after-school activities if 240 total 7th graders attend Maria's school? Write the numerical answer only.

A movie theater randomly samples the types of admission tickets sold on Friday in the afternoon and the evening. If 400 tickets are sold on a Friday afternoon, use your inference and proportional reasoning skills to determine how many of those 400 tickets would be adult tickets. Type your numerical answer only.

Using your inference skills and proportional reasoning, predict the number of purple jellybeans in a bag of 200 total jellybeans if a random sample of 25 resulted in 4 purple jellybeans. I predict there will be _________ purple jellybeans.

Which size random sample is likely to provide the most trustworthy results?

• 5

• 10

• 30

• There is no difference.

Trinity asked a random sample of 50 students at her school if they brought lunch from home today. If 30 answered “yes,” about what percent of students at Trinity’s school brought lunch from home today?

• 15%

• 30%

• 50%

• 60%

Johanna was running for class president. She wanted to know if she had a good chance of winning the election, so she decided to have her classmates help her with surveys. Michael surveyed a random sample of 10 students from the school. 7 of them said they would vote for Johanna. If there are 230 students in the school, and all of them vote, what is Michael’s best estimate of the number of students who would vote for Johanna? _________ students

A sample should be

• representative of  only middle school students only

• a very large group

• representative of the population

• representative of people who volunteer

Each dot represents 1 day. How many days were recorded?

• 9

• 21

• 20

• 105

Terry made the dot plot above to chart the amount of time, in minutes, that it took students to eat breakfast in the morning. How many students took 5 or more minutes to eat their breakfast?

• 11

• 12

• 14

• 16

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