Chapter 13, Problem 36E

a)

To determine

To explain the meaning of statistically significant results.

Answer to Problem 36E

The rate of depression showed by swimmer is low which unlikely due to natural sampling variation.

Explanation of Solution

The meaning of "Significant differences" is that the differences in the scores are too large to be due to chance. Therefore, the rate of depression showed by swimmer is low which unlikely due to natural sampling variation.

b)

To determine

To find the type of study.

Answer to Problem 36E

The retrospective observational study.

Explanation of Solution

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.

There are two types of Observational study:

Retrospective: The data are collected from the past by going back in time.

Prospective: The data are collected in the future.

The researcher identified a group and evaluated them for depression, so retrospective observational study is appropriate.

c)

To determine

To explain the reason of not justified conclusion of study.

Explanation of Solution

The news report claimed that swimming can prevent depression. There might be possibility that the claimed result is due to lurking variables. That is, if the swimmer is rich then he/she can pay for access a pool which makes him happier. Therefore, this made a not justified conclusion of the study.

d)

To determine

To construct a design of the study.

Explanation of Solution