Think About It! Section
Now it's time to test yourself to check your understanding of the material in this lesson. Be sure to also try the Practice quiz in Canvas (you can take that multiple times to see more practice problems).
Select the answer you think is correct - then click the right arrow to proceed to the next question.
Question 1
Which of the following is not an example of probability sampling?
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The correct answer is convenience sampling - because a convenience sample is a type of haphazard sample that does not require the use of probability when obtained. There is no random process used in the selection process.
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The correct answer is convenience sampling - because a convenience sample is a type of haphazard sample that does not require the use of probability when obtained. There is no random process used in the selection process.
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Correct. Because a convenience sample is a type of haphazard sample that does not require the use of probability when obtained. There is no random process used in the selection process.
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The correct answer is convenience sampling - because a convenience sample is a type of haphazard sample that does not require the use of probability when obtained. There is no random process used in the selection process.
Question 2
Which of the following surveys would have the smallest margin of error?
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Correct. A sample size n = 1,600 from a population of 50 million - because the margin of error is only affected by sample size and not by the size of the population.
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The correct answer is a sample size n = 1,600 from a population of 50 million - because the margin of error is only affected by sample size and not by the size of the population.
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The correct answer is a sample size n = 1,600 from a population of 50 million - because the margin of error is only affected by sample size and not by the size of the population.
Question 3
Suppose a recent survey finds that 80% of Penn State students prefer that fall semester begins after Labor Day. The results of this survey were based on opinions expressed by 200 Penn State students. Which of the following represents the calculation of the margin of error for this survey?
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The correct answer is \(\frac{1}{\sqrt{200}}\) - because as defined in the textbook, the margin of error calculation takes the square root of the sample size and divides it into 1.
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The correct answer is \(\frac{1}{\sqrt{200}}\) - because as defined in the textbook, the margin of error calculation takes the square root of the sample size and divides it into 1.
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Correct. \(\frac{1}{\sqrt{200}}\) - because as defined in the textbook, the margin of error calculation takes the square root of the sample size and divides it into 1.
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The correct answer is \(\frac{1}{\sqrt{200}}\) - because as defined in the textbook, the margin of error calculation takes the square root of the sample size and divides it into 1.
Question 4
Suppose a margin of error for a poll is 4%. What is the correct interpretation of the margin of error for this poll? In about 95% of all samples of this size, the _________.
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Correct. Difference between the sample percent and the population percent will be within 4% - because the margin of error gives us the range from our sample value within which we expect the population value to lie.
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The correct answer is: difference between the sample percent and the population percent will be within 4% - because the margin of error gives us the range from our sample value within which we expect the population value to lie.
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The correct answer is: difference between the sample percent and the population percent will be within 4% - because the margin of error gives us the range from our sample value within which we expect the population value to lie.
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The correct answer is: difference between the sample percent and the population percent will be within 4% - because the margin of error gives us the range from our sample value within which we expect the population value to lie.
Question 5
In order to survey the opinions of its customers, a restaurant chain obtained a random sample of 30 customers from each restaurant in the chain. Each selected customer was asked to fill out a survey. Which one of the following sampling plans was used in this survey?
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The answer is: stratified sampling - because with stratified sampling, a random sample is obtained from each and every subset found in the population. The collection of all these random samples forms the stratified sample. With cluster sampling, a random sample of subsets is obtained from all possible subsets in the population. NOT all subsets are sampled. ALL units found in each of the selected subsets are then selected to form a cluster sample.
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Correct. Stratified sampling - because with stratified sampling, a random sample is obtained from each and every subset found in the population. The collection of all these random samples forms the stratified sample. With cluster sampling, a random sample of subsets is obtained from all possible subsets in the population. NOT all subsets are sampled. ALL units found in each of the selected subsets are then selected to form a cluster sample.
Question 6
Eighty individuals who wish to lose weight are randomly divided into two groups of 40. One group is given an exercise program to follow while the other group follows a special diet. After three months, the researcher compares mean weight losses in the two groups. What type of study is this?
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Correct. The answer is a randomized experiment because the researcher randomly assigns subjects to their treatment groups (i.e. whether they did the exercise program or used the special diet).
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This is a randomized experiment because the researcher randomly assigns subjects to their treatment groups (i.e. whether they did the exercise program or used the special diet).
Question 7
Which type of randomization plays an important role in experiments?
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Both are important in experiments. Randomizing the type of treatment alleviates bias whenever groups are being compared. Randomizing the order of treatment is important when the same subject is given more than one treatment as in a matched-pair design.
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Both are important in experiments. Randomizing the type of treatment alleviates bias whenever groups are being compared. Randomizing the order of treatment is important when the same subject is given more than one treatment as in a matched-pair design.
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Correct. Both are important in experiments. Randomizing the type of treatment alleviates bias whenever groups are being compared. Randomizing the order of treatment is important when the same subject is given more than one treatment as in a matched-pair design.
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Both are important in experiments. Randomizing the type of treatment alleviates bias whenever groups are being compared. Randomizing the order of treatment is important when the same subject is given more than one treatment as in a matched-pair design.
Question 8
A researcher conducts a study to determine whether or not smoking causes lung cancer. What is the explanatory variable in this study?
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Correct. Whether or not someone smokes - because the explanatory variable is the variable that defines the groups being compared and is the variable thought to explain any differences in the response or outcome variable.
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The correct answer is whether or not someone smokes - because the explanatory variable is the variable that defines the groups being compared and is the variable thought to explain any differences in the response or outcome variable.