In: Statistics and Probability
Does daily cardio exercise make subjects perform better on tests
of intelligence? A study was conducted in which the daily habits of
45 college students were documented, focusing on the number of
hours spent on exercise in a week. After a week, the subjects were
given a computer-based intelligence test on which they receive a
score on a 0 to 100 point scale. Their scores were compared with
how many hours they spent exercising that week.
Select one or more:
The explanatory variable is the score on the computer-based intelligence test.
The response variable is the score on the computer-based intelligence test.
The explanatory variable is the number of hours exercised during the week.
The response variable is the number of hours exercised during the week.
This is best described as an observational study.
This study is best described as an experiment.
A local corporation was interested in the purchasing habits of Monterey County residents. Specifically one of the things they were interested in was the proportions of residents that did a major home improvement project in the last year. The corporation used a list of all households to take a simple random sample of households. The researcher then visited each of the sampled homes and found that 21 of 100 homes had completed a major home improvement project.
For this situation which of the following would be most likely to lead to a problem of non-response.
Select one:
If the survey only looked at 100 households even though there are over 200,000 homes in Monterey County.
If the list of households only included homes that had been sold to a new owner in the last 10 years.
If the researchers actually visited 400 households but only 100 of them were willing to answer the questions on the survey.
If some of the subjects did not understand what the researcher meant by “home improvement” projects.
A researcher wants to find out how college students feel about their social security system. Which of the following unbiased methods could the researcher use?
Select one or more:
The researcher places a poll question on the main university website and allow students to vote whether or not they like the system.
The researcher sets up a booth outside of the large classroom building and ask students to fill out a survey as they pass.
The researcher randomly selects 10 classes and succesfully asks all the students in those classes to fill out an anonymous survey.
The researcher places a survey in the campus paper which students could cut out and mail to the researcher.
The researcher takes a random sample from the enrollment list of the college and surveys the selected students.
(1)
(a)
Correct option:
The response variable is the score on the computer-based intelligence test.
The explanatory variable is the number of hours exercised during the week.
(b)
Correct option:
This study is best described as an experiment.
In experimental design the researcher manipulates the independent variable in order to study its effect on the dependent variable. Here exercising per week is manipulated in order to study its effect on intelligence test.
(2)
Correct option:
If the researchers actually visited 400 households but only 100 of them were willing to answer the questions on the survey.
Explanation:
Many persons selected for the survey may not take the trouble to the survey questions because there is no compulsion or incentive to answer.
(3)
Correct option:
The researcher takes a random sample from the enrollment list of the college and surveys the selected students.
Explanation:
Taking a random sample from enrollment list gives unbiased sample.