Lec 8

One-Way Between-Subjects ANOVA

A statistical test used to compare the means of three or more independent groups.

Null Hypothesis

The hypothesis that states there is no effect or difference; in this context, it posits that the mean attention scores in the Caffeine groups are the same.

Alternative Hypothesis

The hypothesis that states there is an effect or difference; in this case, it suggests that the mean attention scores among the Caffeine groups are not the same.

Dependent Variable (DV)

The variable that is measured in an experiment; in this example, it is the performance on a sustained attention task.

Independent Variable (IV)

The variable that is manipulated in an experiment; in this case, it refers to the level of caffeine.

Confidence Interval

A range of values that is likely to contain the population parameter with a specified level of confidence.

Effect Size

A quantitative measure of the magnitude of a phenomenon; in this case, it reflects the impact of caffeine on attention.

Homogeneity of Variance

An assumption used in ANOVA that states the variances among the different groups should be approximately equal.

Normality Assumption

The assumption that the residuals of the data are normally distributed, which is necessary for the validity of ANOVA.

Post-hoc tests

Statistical analyses conducted after an ANOVA to determine which specific group means are significantly different.

Levene's Test

A statistical test used to assess the homogeneity of variances across groups.

Tukey's Post-hoc Test

A post-hoc analysis that assesses all possible pair-wise comparisons while controlling the familywise error rate.

Cohen's d

A measure of effect size that expresses the size of the difference between two means relative to the variability observed in the data.

Kruskal-Wallis Test

A nonparametric alternative to the One-Way ANOVA used when the assumptions of ANOVA are violated.

Familywise Error Rate (FWER)

The probability of making one or more Type I errors when conducting multiple comparisons.

Eta Squared (η²)

A measure of effect size that indicates the proportion of variance explained by an independent variable in the context of ANOVA.

Omega Squared (ω²)

An unbiased estimate of effect size that indicates the proportion of variance explained by a factor in a population.

Standard Deviation (SD)

A measure of the amount of variation or dispersion in a set of values.

Type I Error

The incorrect rejection of a true null hypothesis (also known as a false positive).

Type II Error

The failure to reject a false null hypothesis (also known as a false negative).