If you’d like to know if 2 groups of people score similarly on 1 dichotomous variable, you’ll compare 2 independent proportions. There’s two basic ways to do so: the chi-square independence test and; the z-test for 2 independent proportions. These tests yield identical significance levels but the z-test approach allows you to compute a confidence interval for the difference between […]
A sign test for one median is often used instead of a one sample t-test when the latter’s assumptions aren’t met by the data. The most common scenario is analyzing a variable which doesn’t seem normally distributed with few (say n < 30) observations. * This tutorial shows how to run and interpret a sign test in SPSS. We’ll […]
There’s two basic tests for testing a single proportion: the binomial test and the z-test for a single proportion. For larger samples, these tests result in roughly similar significance levels. However, the binomial test only comes up with a 1-tailed p-value unless the hypothesized proportion = 0.5. Moreover, it can’t compute a confidence interval for your proportion. The […]
SPSS nonparametric tests are mostly used when assumptions aren’t met for other tests such as ANOVA or t-tests.* Second, nonparametric tests are suitable for ordinal variables too. In rare cases they may have more statistical power than standard tests. Not sure which (nonparametric) test to use? You’ll quickly find the answer in Simple Overview Statistical Comparison Tests. Nonparametric Tests – One Sample SPSS Kolmogorov-Smirnov Test for […]
