A psychologist wonders whether children who are adopted differ in intelligence from those who are not. She obtains a sample of 75 children who were adopted, and she tests them. Their IQ score is 104.5

The population mean () is 100.

7. Identify the population of interest.

8. Identify the sample.

9. Identify the independent variable(s).

10. Identify the dependent variable(s).

In a 2010 report, Goodman and Greaves (2010) reported findings from an analysis of data from participants in a large research project in the United Kingdom, the Millennium Cohort Study. They stated that "...while it is true that cohabitating parents are more likely to split up than married ones, there is very little evidence to suggest that this is due to a causal effect of marriage. Instead, it seems simply that different sorts of people choose to get married and have children, rather than to have children as a cohabitating couple, and that those relationships with the best prospects of lasting are the ones that are most likely to lead to marriage" (p. 1).

11. Identify the population of interest.

12. Identify the sample.

13. Identify the independent variable(s).

14. Identify the dependent variable(s).