Research Design and Correlation Coefficient

Flashcards covering key concepts from Research Design, Correlation Coefficients, and related statistical tests.

Research Design

A plan to collect, measure, and analyze data in order to answer research questions.

Between Subjects Design

Participants are assigned to different groups or samples, where they are observed only once.

Within Subjects Design

A research design in which the same participants are observed in each group or treatment.

Repeated Measures Design

Includes multiple measurements from the same participants, typically in pretest-posttest scenarios.

Matched Samples Design

An experimental method where participants are matched based on common characteristics before assignment to conditions.

Correlation Coefficient

A numerical measure that describes the strength and direction of a relationship between two variables.

Pearson's r

A measure of the linear relationship between two interval or ratio measured variables.

Positive Correlation

When one variable increases, and the other also increases.

Negative Correlation

When one variable increases, and the other decreases.

No Correlation

There is no clear relationship between the two variables.

Confounding Variable

An external variable that influences both the independent and dependent variables.

Hybrid Error

Mistakenly attributing causation based solely on correlation without accounting for other variables.

Type I Error (α)

Rejecting a true null hypothesis, falsely indicating an effect when none exists.

Type II Error (β)

Failing to reject a false null hypothesis, missing a true effect.

Power of a Test

The probability that a test correctly rejects a false null hypothesis.

Null Hypothesis

The assumption that there is no effect or difference in a population.

Interval Estimation

A range of values used to estimate the true population parameter.

Confidence Interval

A range of plausible values for a population parameter based on sample data.

Interval Variables

Numerical values with equal intervals but no true zero.

Ratio Variables

Numerical values with both equal intervals and a true zero.