Lec 7-01

Paired t-test

A statistical test used to compare the means of two related groups, analyzing dependent samples.

Dependent Variable (DV)

The variable that is measured in an experiment, which is expected to change as a result of manipulations in the independent variable.

Normality Assumption

The assumption that the distribution of the sample means differs from a normal distribution, specifically that the sampling distribution of mean differences is normally distributed.

Confidence Interval

A range indicating the reliability of an estimate, suggesting where the true population parameter may lie, typically with a specified level of confidence.

Effect Size

A quantitative measure of the magnitude of a phenomenon, which provides an idea of the practical significance of a study's findings.

Skewness

A measure of the asymmetry of the probability distribution of a real-valued random variable about its mean.

Kurtosis

A statistical measure that describes the distribution's tails in relation to its overall shape and indicates the presence of outliers.

Shapiro-Wilk Test

A statistical test that assesses whether a sample comes from a normally distributed population, with specific focus on the data's adherence to normality.

Null Hypothesis (H0)

A statement that there is no effect or no difference, which the researcher seeks to test against.

Alternative Hypothesis (H1)

A statement that indicates the presence of an effect or a difference, which the researcher aims to support in a study.

Cohen's d

A measure of effect size that expresses the difference between two means in standard deviation units.

Wilcoxon Signed-Rank Test

A nonparametric statistical test used to compare two related samples, particularly when the normality assumptions of the t-test are not met.

Rank-Biserial Correlation

A measure of effect size that quantifies the strength of a relationship in nonparametric tests by comparing ranks.

Probability of Superiority (PS Paired)

The probability that a randomly selected individual from one condition will have a higher score than a randomly selected individual from another condition.