SPSS transformations between DO IF … and END IF are applied only to cases (rows of data) that satisfy one or more conditions. In many cases, IF is a faster way to accomplish the same results. SPSS Do If Example Say we’d like to convert people’s monthly income into income classes. We may want to use different cut […]
For testing if 3 or more variables have identical population means, our first option is a repeated measures ANOVA. This requires our data to meet some assumptions -like normally distributed variables. If such assumptions aren’t met, then our second option is the Friedman test: a nonparametric alternative for a repeated-measures ANOVA. Strictly, the Friedman test can […]
SPSS Cochran Q test is a procedure for testing if the proportions of 3 or more dichotomous variables are equal in some population. These outcome variables have been measured on the same people or other statistical units. SPSS Cochran Q Test Example The principal of some university wants to know whether three examns are equally difficult. Fifteen […]
The sign test for two medians evaluates if 2 variables measured on 1 group of cases are likely to have equal population medians.* It can be used on either metric variables or ordinal variables. For comparing means rather than medians, the paired samples t-test and Wilcoxon signed-ranks test are better options. Adratings Data We’ll use adratings.sav throughout this tutorial. It holds data on 18 respondents […]
For comparing two metric variables measured on one group of cases, our first choice is the paired-samples t-test. This requires the difference scores to be normally distributed in our population. If this assumption isn’t met, we can use Wilcoxon S-R test instead. It can also be used on ordinal variables -although ties may be a real issue for Likert items. […]
SPSS McNemar test is a procedure for testing if the proportions of two dichotomous variables are equal in some population. The two variables have been measured on the same cases. SPSS McNemar Test Example A marketeer wants to know whether two products are equally appealing. He asks 20 participants to try out both products and […]
ANOVA -short for “analysis of variance”- is a statistical technique for testing if 3(+) population means are all equal. ANOVA – Null Hypothesis Test Statistic – F Assumptions for ANOVA Effect Size – (Partial) Eta Squared ANOVA – Post Hoc Tests The basic idea behind ANOVA: are 3(+) population means all equal? The two simplest […]
The Mann-Whitney test is an alternative for the independent samples t test when the assumptions required by the latter aren’t met by the data. The most common scenario is testing a non normally distributed outcome variable in a small sample (say, n < 25).* The Mann-Whitney test is also known as the Wilcoxon test for independent samples -which shouldn’t be confused […]
Null Hypothesis Assumptions Chi-Square Independence Test in SPSS Output Reporting Null Hypothesis Chi-Square Independence Test A chi-square independence test evaluates if two categorical variables are associated in some population. We’ll therefore try to refute the null hypothesis that two categorical variables are (perfectly) independent in some population.If this is true and we draw a sample from this population, then we […]
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 […]
SPSS one-sample chi-square test is used to test whether a single categorical variable follows a hypothesized population distribution. SPSS One-Sample Chi-Square Test Example A marketeer believes that 4 smartphone brands are equally attractive. He asks 43 people which brand they prefer, resulting in brands.sav. If the brands are really equally attractive, each brand should be chosen by roughly […]
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 […]
Independent Samples T-Test SPSS Independent Samples T-Test Independent Samples T-Test Other SPSS T-Test Tutorials SPSS Paired Samples T-Test SPSS One Sample T-Test T-Test Background Tutorials Z-Scores – What and Why? What is a Dichotomous Variable?
