Читать книгу The Handy Psychology Answer Book - Lisa J. Cohen - Страница 235

Many studies compare one or more variables across different groups. For example, does Drug A reduce depression more than Drug B? Do children from bilingual homes learn languages more quickly than children from monolingual (single language) homes? Is there more crime during the week of the full moon than during the week before? Several statistical tests help determine whether the means of two or more groups differ from each other and whether the difference found is statistically significant. Such tests include the Student’s t-test, the analysis of variance (ANOVA), and several variations on the ANOVA test (e.g., analysis of repeated measures (ANOVAR) and multivariate analysis of variance (MANOVA)). All of these tests compare the mean score between two or more groups, taking into account the variation within the groups (i.e., the standard deviation). The standard deviation is important because the greater the variation within the two groups, the more likely that the difference between the two groups is due to chance and would not be repeated if the same test were performed on a different sample.