Intro to T-tests

INTRODUCTION TO T-TESTS

  • Focus on analysis of means differences among groups.

KEY CONCEPTS

  • Correlation & regression: Assess relationships between variables.

  • T-tests: Analyze differences between means.

  • ANOVAs: Compare differences among 3+ means.

TYPES OF T-TESTS

  1. Independent Two Sample T-Test

    • Compares means of two distinct populations.

  2. Related Samples (Paired Samples) T-Test

    • Compares means from the same participants at two points in time or under two conditions.

  3. One Sample T-Test

    • Compares the sample mean to a known population mean.

NONPARAMETRIC OPTIONS

  • Mann-Whitney U Test: Alternative for independent two sample t-test when assumptions are violated.

  • Wilcoxon Test: Alternative for paired samples t-test for small sample sizes or non-normal distribution.

EXAMPLES OF T-TEST APPLICATIONS

  • Difference in weekly alcohol consumption between employed vs. unemployed individuals.

  • Mean aggression scores before vs. after an anger management course.

  • Comparison of unemployment levels in ex-offenders to the general population mean.