Q: In a Pew Research Center poll, 58% of 1182 respondents said they like to drive. What is the actual number of respondents who said they like to drive? Use the formula $$\text{Number} = \text{Percentage} \times \text{Total}.$$

$$\text{Number} = 0.58 \times 1182 = 685$$

Question 1

A USA Today online poll asked, 'How often do you seek medical information online?' Of 1072 Internet users who chose to respond, 38% said 'frequently.' What is the main problem with this type of sampling method?

Accepted Answer

It is a voluntary response sample, which can lead to bias because only those with strong opinions are likely to respond.

Question 2

A survey on 'Should guys pay for the first date?' received 85% 'yes' responses from 1148 people who chose to participate. Which of the following best describes the value 85% in this context?

Accepted Answer

It is a statistic because it is calculated from a sample of respondents.

Question 3

In a clinical trial, 150 patients were treated with oxygen and 148 with a placebo. The study was described as 'randomized and double-blind.' What does 'double-blind' mean in this context?

Accepted Answer

Neither the patients nor the researchers know which treatment each patient receives.

Question 4

A study found a high correlation between the divorce rate in Maine and per capita margarine consumption in the US. What is the best conclusion?

Accepted Answer

Correlation does not imply causation; the relationship is likely coincidental.

Question 5

A quality control plan selects every 500th Lipitor pill for testing. What type of sampling is this?

Accepted Answer

Systematic sampling

Question 6

Gallup surveys 500 randomly selected men and 500 randomly selected women to test for gender differences in online purchases. What type of sampling is this?

Accepted Answer

Stratified sampling

Question 7

A computer randomly selects 500 numbers from a list of all 1,736,997 adults in Manhattan, and those adults are surveyed. What type of sampling is this?

Accepted Answer

Simple random sampling

Question 8

A statistics student surveys only fellow statistics students. What type of sampling is this?

Accepted Answer

Convenience sampling

Question 9

The Commissioner of Major League Baseball randomly selects one team from the American League and one from the National League, then surveys all players on those teams. What type of sampling is this?

Accepted Answer

Cluster sampling

Question 10

Two questions are asked: (1) 'Are you in favor of the Defense of Marriage Act?' and (2) 'Are you in favor of an act that for federal and state aid, only heterosexual marriages should be recognized?' What statistical concept is illustrated by the difference in wording?

Accepted Answer

Wording bias, which can influence how people respond.

Question 11

California has 39,776,830 residents and Wyoming has 573,520. Are these population sizes discrete or continuous data?

Accepted Answer

Discrete, because the number of residents can only take whole number values.

Question 12

What is the level of measurement for the number of residents in different states?

Accepted Answer

Ratio, because the data have a true zero and meaningful ratios.

Question 13

What is a major problem with surveying state residents by mailing questionnaires to 10,000 randomly selected people?

Accepted Answer

Nonresponse bias, because many people may not return the questionnaire.

Question 14

If we randomly select 50 full-time workers in each of the 50 states, what type of sample is obtained?

Accepted Answer

Stratified sampling

Question 15

If we randomly select two states and survey all of their adult residents, what type of sample is obtained?

Accepted Answer

Cluster sampling

Question 16

A U-Turn protein bar claims to have '125% less fat than the leading chocolate candy brands.' What is wrong with this claim?

Accepted Answer

It is impossible to have 125% less fat; a reduction greater than 100% is not meaningful.

Question 17

In a Pew Research Center poll, 58% of 1182 respondents said they like to drive. What is the actual number of respondents who said they like to drive? Use the formula $$	ext{Number} = 	ext{Percentage} 	imes 	ext{Total}.$$

Accepted Answer

$$	ext{Number} = 0.58 	imes 1182 = 685$$

Question 18

In a Pew Research Center poll, 331 of 1182 respondents said driving is a chore. What percentage of respondents said this? Use the formula $$	ext{Percentage} = \frac{	ext{Number}}{	ext{Total}} 	imes 100\%.$$

Accepted Answer

$$\frac{331}{1182} 	imes 100\% \approx 28\%$$

Question 19

At Albany Medical Center, every 10th newborn baby is selected and their body temperature (in degrees Fahrenheit) is measured. What is the level of measurement and the sampling method?

Accepted Answer

Level: Interval; Sampling: Systematic

Question 20

In each of the 50 states, 50 voters are randomly selected and their political party affiliations are identified. What is the level of measurement and the sampling method?

Accepted Answer

Level: Nominal; Sampling: Stratified

Question 21

A pollster stops each person passing her office and asks them to rate the last movie they saw on a scale of 1 to 4 stars. What is the level of measurement and the sampling method?

Accepted Answer

Level: Ordinal; Sampling: Convenience

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