Confidence Intervals, Hypothesis Testing, Statistical Tests - Psyc 71 W26

Confidence Interval (CI)

A statistical range that is likely to contain the true population parameter, calculated from sample data.

Margin of Error (MoE)

The largest likely sampling error in a sample statistic, often expressed as a percentage.

t Distribution

A probability distribution used to estimate population parameters when the sample size is small and the population standard deviation is unknown.

Null Hypothesis (H0)

A statement suggesting that there is no effect or difference, and any observed effect is due to sampling error.

Alternative Hypothesis (H1)

A statement indicating the presence of an effect or a difference in the population, suggesting that the observed effect is real.

Degrees of Freedom (df)

The number of independent values or quantities that can vary in a statistical analysis, typically calculated as sample size minus one.

p-value

The probability of obtaining a test statistic at least as extreme as the one observed, assuming the null hypothesis is true.

Standard Error (SE)

An estimate of the variability of a sample statistic, calculated as the sample standard deviation divided by the square root of the sample size.

Sampling Error

The difference between a sample statistic and the corresponding population parameter it estimates.

α (Alpha Level)

The threshold for determining statistical significance; commonly set at 0.05, representing a 5% risk of concluding that a difference exists when there is none.

Hypothesis Testing

A statistical method used to decide whether to reject the null hypothesis based on sample data.

Statistical Hypotheses

Statements that specify the expected relationship or differences in a population, against which data are tested.

Test Statistic

A standardized value that is calculated from sample data during a hypothesis test, used to evaluate the null hypothesis.

Statistical Test

A method used to determine if there is enough evidence to reject a null hypothesis based on sample data.

t-test

A statistical test that compares the means of two groups to see if they are different from each other.

ANOVA

Analysis of Variance; a statistical method used to test differences between two or more means by comparing variance.

Chi Square Test of Association

A test used to determine whether there is a significant association between two categorical variables.

p-value

The probability of observing the test statistic, or something more extreme, under the null hypothesis.

Null Hypothesis (H0)

A statement that there is no effect or no difference, often assumed to be true until evidence indicates otherwise.

Alternative Hypothesis (H1)

A statement that there is an effect or a difference, opposing the null hypothesis.

Signal-to-Noise Ratio

A measure that compares the level of a desired signal to the level of background noise.

Independent Samples t-Test

A t-test used when comparing the means of two independent groups.

Paired Samples t-Test

A t-test used when comparing means from the same group at different times.

F-ratio

The ratio used in ANOVA, comparing variance between groups to the variance within groups.

Degrees of Freedom (df)

The number of independent values or quantities which can vary in an analysis without breaking any constraints.

Expected Frequencies

The frequency of outcomes expected if the null hypothesis were true.

Pearson Product-Moment Correlation

A measure of the strength and direction of association between two continuous variables.

Contingency Table

A table used to display the frequency distribution of variables.

Tukey HSD

A post-hoc test used to find which specific group means are different after a significant ANOVA result.