an association between cholesterol level and the amount of exercise a person gets. For a
randomized block design, it should:
A. Block on gender because it is not associated with cholesterol level.
B. Block on gender because males and females are different.
C. Block on the type of drug because it may be associated with cholesterol level.
D. Block on exercise level because it is associated with cholesterol level.
E. Block on both gender and exercise because blocking on more variables gives more reliable
estimates.
A high school sent a survey to a randomly selected sample of 75 of last year’s graduating class. 27
of those selected did not return the survey. The best plan of action would be to:
A. Use the surveys that were returned and change the sample size to 48 for the analysis.
B. Use the surveys that were returned and leave the sample size at 75 for the analysis.
C. Randomly select 27 additional class members and send the survey to them.
D. Start over with a new sample but use a larger sample size.
E. Follow up with those that did not return the survey to encourage them to respond.
- Which of these is a correct description of the term?
A. A factor is a response variable.
B. Replication means the experiment should be repeated several times.
C. Levels are the same as treatments .
D. Experimental units are the same as subjects .
E. The response variable is the variable directly controlled by the researchers.
The president of an online music streaming service whose customers pay a fee wants to gather
additional information about customers who have joined in the past 12 months. The company plans
to send out an e-mail survey to a sample of current customers with a link that gives participants a
month of streaming service for free once the survey has been completed. They know that musical
tastes vary by geographical region. Which of the following sample plans would produce the most
representative sample of its customers?
A. Choose all of the customers who joined in the last month.
B. Make a list of all the customers who joined in the last 12 months and choose a random sample
of customers on this list.
C. From the list of all customers who joined in the last 12 months, classify customers by the state
in which they live, then choose 10 customers from each state.
D. From the list of all customers who joined in the last 12 months, classify customers by the state
in which they live, then choose 3% of the customers from each state.
E. Make a list of all customers who joined in the last 12 months and choose every 10th customer
on this list.
- The reason we check that np and n (1 – p ) are at least 10 when calculating probabilities in a
binomial situation is to:
A. Ensure that has a binomial distribution.
B. Be sure the sample is random enough.
C. Make sure the distribution of is symmetric enough to use a normal approximation.