Question 1

A survey posted on USA Today’s website asked, “How often do you seek medical information online?” Of 1072 Internet users who chose to respond, 38% said 'frequently.' What is the main issue with this sampling method?

Accepted Answer

It is a voluntary response sample, which can lead to bias because respondents self-select.

Question 2

In the USA Today survey about paying for first dates, 85% of 1148 respondents said 'yes.' Is the value of 85% a statistic or a parameter?

Accepted Answer

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

Question 3

A clinical trial for cluster headache treatment involved 150 patients treated with oxygen and 148 given 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 most appropriate conclusion?

Accepted Answer

Correlation does not imply causation; the relationship may be 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 used?

Accepted Answer

Stratified sampling

Question 7

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

Accepted Answer

Convenience sampling

Question 8

The Commissioner of Major League Baseball randomly selects one team from each league and surveys all players on those teams. What type of sampling is this?

Accepted Answer

Cluster sampling

Question 9

California has 39,776,830 residents and Wyoming has 573,520. What is the level of measurement for the number of residents in each state?

Accepted Answer

Ratio

Question 10

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

Accepted Answer

Stratified sample

Question 11

If you randomly select two states and survey all adult residents in those states, what type of sample is obtained?

Accepted Answer

Cluster sample

Question 12

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

Accepted Answer

It is mathematically impossible to have 125% less fat; this would imply negative fat content.

Question 13

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?

Accepted Answer

684

Question 14

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

Accepted Answer

$$28\%$$

Question 15

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

Accepted Answer

Interval

Question 16

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 for the movie ratings?

Accepted Answer

Ordinal

Question 17

A clinical trial for a new IVF procedure resulted in 239 boys out of 291 births. If the probability of a boy is $$0.5$$, what is the probability of observing 239 or more boys by chance? (Use binomial probability: $$P(X \geq 239)$$ for $$n=291$$, $$p=0.5.)$$

Accepted Answer

Less than 1%

Question 18

Which of the following best describes the difference between statistical significance and practical significance?

Accepted Answer

Statistical significance means the result is unlikely due to chance, while practical significance means the result has real-world impact.

Question 19

A list of all 1,736,997 adults in Manhattan is numbered, and a computer randomly generates 500 numbers to select adults for a survey. What type of sampling is this?

Accepted Answer

Simple random sampling

Question 20

Which of the following is a real-world example of a convenience sample?

Accepted Answer

A researcher surveys people who walk past her office.

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