Making Inferences from Samples about a Population

The election committee for a candidate running for mayor randomly selects 200 men to complete an online survey. The men are asked to identify which mayoral candidate they are most likely to vote for in the upcoming election. Of the 200 men polled, 42 men chose not to answer and 52% indicated they would vote for candidate Ray. Based on these results, what can be inferred about the outcome of the election?

• Ray cannot possible win the election

• 42 percent of the citizens will not vote.

• Ray is the most popular candidate among men voters

• 48 percent of men plan to vote for a candidate other than Ray.

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

Jon finds a box of 350 postcards. He selects a random sample of 75 postcards and finds that 27 already have a stamp on them. Predict the total number of postcards in the box with stamps on them.

• 9,450 postcards

• 126 postcards

• 13 postcards

• 5 postcards

A(n) _______________________ is an entire group of objects from which data can be collected.

• Inference

• population

• random sample

• sample

• valid inference

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

• Inference

• population

• random sample

• sample

• valid inference

A(n) _______________________ is one that is true about a population based on a representative sample.

• population

• random sample

• sample

• valid inference

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.

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.

True or False: Random samples can represent the population

• True

• False

I drew 10 names from a hat containing the names of every student that I teach, what type of sample have I taken?

• A random sample.

• A biased sample.

• A systematic sample.

• A voluntary response sample.