"In studies of monozygotic (identical) twins, the correlation between intelligence (IQ) scores is 0.85.


b. What are the variables being measured?"

Verified step by step guidance

1. Identify the context of the problem: it involves studies of monozygotic (identical) twins and their intelligence scores.
2. Understand that the correlation mentioned (0.85) measures the strength and direction of a linear relationship between two variables.
3. Recognize that the variables being measured are the intelligence (IQ) scores of each twin in the pair.
4. Since the study involves pairs of twins, the two variables are the IQ score of Twin 1 and the IQ score of Twin 2.
5. Therefore, the variables being measured are the IQ scores of the two individuals in each monozygotic twin pair.

Key Concepts

Variables in a Study

Variables are measurable traits or characteristics that can vary among subjects in a study. Identifying variables is essential to understand what is being observed or tested, such as IQ scores in twins. Variables can be independent, dependent, or simply measured attributes.

Correlation Coefficient

The correlation coefficient quantifies the strength and direction of a linear relationship between two variables, ranging from -1 to 1. A value of 0.85 indicates a strong positive relationship, meaning as one twin's IQ increases, the other twin's IQ tends to increase similarly.

Monozygotic Twins in Research

Monozygotic twins share nearly identical genetic makeup, making them ideal for studying genetic and environmental influences on traits like intelligence. Measuring variables in such twins helps isolate genetic factors by comparing similarities in traits such as IQ scores.