Random Sampling and Data Inferences

Which city, Nashville or Dallas, has the lowest Q1?

• Nashville

• Dallas

The value found by adding up a set of data points and dividing by the total number of points.

• Mean

• Median

• Mode

• Data

A researcher asked five of his doctor friends if they thought the new Brand X medicine that he developed was effective. Four responded "yes." The researcher used the results to write a TV advertisement claiming that "4 out of 5 doctors prefer Brand X medicine." Is this a valid inference? Explain.

• No, because the doctors asked are not a representative sample of the population of doctors.

• No, because 4 doctors said yes out of 9 who were asked.

• Yes, because the doctors asked are a representative sample of the population of doctors.

• Yes, because 4 doctors said yes out of the 5 who were asked.

What inference can you draw from this survey?

• I can infer that most students in this school like pizza.

• I can infer that very few students like hamburgers.

• I can infer that their favorite is corn dogs.

• I can infer that most students in this school like hamburgers.

Which method is most likely to produce a random sample of the members of your class?

• listing the first six students that come to mind

• choosing the five oldest students in the class

• writing the name of each student on a separate piece of paper and then drawing these slips from a hat

• selecting the first six students to arrive at class

Sam tested every 50th candy bar from the assembly line to make sure there were enough peanuts in each bar.  He found 15% did not have enough peanuts.  How many candy bars do not have enough peanuts if the factory produces 20,000 candy bars?

• 300

• 3,000

• 300,000

• 50

A travel club has 3,000 members. A random sample of 50 of the club members found that 12 people like mountain vacations best. Which statement is NOT supported by the sample data?

• Twenty-four percent of those sampled say they like mountain vacations best.

• An estimated 720 club members would likely say they enjoy mountain vacations best.

• Almost one-quarter of club members would likely say they enjoy mountain vacations best.

• More than 2,500 club members would likely say they prefer other vacations over mountain vacations.

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)  

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CCSS.7.RP.A.3

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.

(a)  

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CCSS.7.RP.A.3

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%