A researcher studying depression in relation to five predictor variables decides to include five more variables in the study because the literature reveals that they may also be involved in depression. Consequently, the researcher will do which of the following?

a. Use a larger sample size.
b. Set beta at a lower level.
c. Perform additional reliability and validity tests.
d. Change the design of the research from correlational to descriptive.

a.Use a larger sample size.

Explanation:

The sample size can be determined as the number of individuals samples taken to qualitate and quantitate the parameters taken for the study. The large sample size enables the researchers to determine the average value for each set parameter without the occurrence of errors in the data.

According to the given situation, as the number of variables or parameters of the study increases the sample size is required to be increased. This is necessary to include all the variables in the available sample size to reach upto a valid conclusion for each variable. The selected samples must show correlation with the variables.