A Psychologist Conducts Research Using the Twin-Study Method

question 7

Multiple Choice

A psychologist conducts research using the twin-study method. He administers a need for Achievement scale to sets of monozygotic and dizygotic twins and finds a correlation of .50 between the scores for pairs of monozygotic twins. If this study is to demonstrate evidence for a genetic influence on need for Achievement, what would we expect the correlation to be between scores for pairs of dizygotic twins?

• A) Higher than .50
• B) Lower than .50
• C) Very close to .50
• D) There is no way to demonstrate a genetic influence with these data.

---

Definitions:

Degrees of Freedom

The number of independent values or quantities that can vary in the analysis without breaking any constraints, relevant in statistical tests to assess the validity of the test.

Preservatives

Substances used in food processing and preservation to prevent spoilage and decay caused by microbial growth or undesirable chemical changes.

Hours Until Spoilage

The estimated time it takes for food or other perishable items to become unsuitable for consumption due to degradation or the growth of harmful organisms.

Rejection Region

The range of values for which a null hypothesis is rejected in a hypothesis testing scenario.