1. Statistics and Research methods Wiskunde voor HMI Bijeenkomst 5

2. t Test for Independent Means Between-subjects design (two experimental groups) Scores of two groups – Experimental group and control group Use differences between means Population 1: people in experimental group Population 2: people in control group Comparison distribution: distribution of differences between means, μ = 0, δ unknown, estimate from samples →S difference df = df 1 + df 2 with df 1 =N 1 – 1 ; df 2 = N 2 - 1

3. Analysis of variance (ANOVA) Comparison of more than two groups – ANOVA used for two groups gives the same result as t-test for independent means F distribution (F table) F ratio = between-groups estimate of population variance / within-groups estimate of poputation variance df Between = Ngroups – 1 df Within = df 1 + df 2 + … + df Ngroups

4. Other issues on paper CHI-square test Reliability of measures Factor analysis