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a)
To identify whether the observational study or experimental study.
a)
Answer to Problem 1.14E
This is an observational study.
Explanation of Solution
Given:
One study of cell phones and the risk of brain cancer looked at a group of 469 people who have brain cancer. The investigators matched each cancer patient with a person of the same sex, age, and race who did not have brain cancer, then asked about use of cell phones." Result: "Our data suggest that use of hand-held cellular telephones is not associated with risk of brain cancer."
First need to understand about the experimental study and observational study:
Experimental study: Assigning people or things to groups and applying some treatment to one group, while the other group does not receive the treatment.
Observation study: In an observational study, measure or survey members of a sample without trying to affect them.
This study is an observation study. As in this study, patients do not influence for treatment, they just observing and asking about use of cell phone.
b)
To find individuals and variables.
b)
Answer to Problem 1.14E
Individuals are 469 cancer and no brain cancer patients and the variables are age, sex, race and cell phone use.
Explanation of Solution
Given:
One study of cell phones and the risk of brain cancer looked at a group of 469 people who have brain cancer. The investigators matched each cancer patient with a person of the same sex, age, and race who did not have brain cancer, then asked about use of cell phones." Result: "Our data suggest that use of hand-held cellular telephones is not associated with risk of brain cancer."
First need to know what is mean by individual.
Individuals are the objects described by the set of the data.
Therefore, in this study, the individuals are that 469 cancer patients and their corresponding person with no brain cancer. There might be some additional variables coming in this picture, but the main variables are sex, age, race and use of cell phone.
Chapter 1 Solutions
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