T Test, Chi-Square Test, Correlation, ANOVA, Regression, Nonparametric Tests,
A Spearman rank correlation is a number between -1 and +1 that indicates to what extent 2 variables are monotonously related. Spearman Correlation – Example Spearman Rank Correlation – Basic Properties Spearman Rank Correlation – Assumptions Spearman Correlation – Formulas and Calculation Spearman Rank Correlation – Software Spearman Correlation – Example A sample of 1,000 […]
What is a Kolmogorov-Smirnov normality test? SPSS Kolmogorov-Smirnov test from NPAR TESTS SPSS Kolmogorov-Smirnov test from EXAMINE VARIABLES Reporting a Kolmogorov-Smirnov Test Wrong Results in SPSS? What is a Kolmogorov-Smirnov normality test? The Kolmogorov-Smirnov test examines if scores are likely to follow some distribution in some population.For avoiding confusion, there’s 2 Kolmogorov-Smirnov tests: there’s the one […]
SPSS CORRELATIONS creates tables with Pearson correlations and their underlying N’s and significance levels. For Spearman rank correlations and Kendall’s tau, use NONPAR-CORR. Both commands can be pasted from Analyze Correlate Bivariate. This tutorial quickly walks through the main options. We’ll use freelancers.sav throughout and we encourage you to download it and follow along with the examples. User Missing Values Before running any […]
We had 5 judges taste and rank 6 different beers. The data -shown above- are in beertest.sav. For answering which beer was rated best, a Friedman test would be appropriate because our rankings are ordinal variables. A second question, however, is to what extent do all 5 judges agree on their beer rankings? If our judges don’t agree at […]
Summary What’s the easiest way to obtain confidence intervals for Pearson correlations? Sadly, we couldn’t find these often requested statistics anywhere in SPSS. The best we encountered on the web were some ancient macros that, well… how to say this delicately… didn’t excel in user friendliness. This tutorial therefore proposes a freely downloadable, menu based tool […]
Creating a scatterplot in SPSS is pretty straightforward. However, I sometimes like to take a quick look at all scatterplots among a set of variables. So I created a simple tool that creates all of them in one click. All Scatterplots Tool – Download and Install First off, make sure you have SPSS version 18 or higher with the SPSS Python Essentials properly installed […]
Correlation Test – What Is It? Null Hypothesis Assumptions Correlation Test in SPSS Reporting Correlation Test – What Is It? A (Pearson) correlation is a number between -1 and +1 that indicates to what extent 2 metric variables are linearly related. It’s best understood by looking at some scatterplots. In short, a correlation of -1 indicates a perfect linear descending relation: higher scores on […]
Cramér’s V is a number between 0 and 1 that indicates how strongly two categorical variables are associated.If we’d like to know if 2 categorical variables are associated, our first option is the chi-square independence test. A significance level close to zero means that our variables are very unlikely to be completely unassociated in some population. However, this does not […]
What and Why? Chi-Square Independence Test – What Is It? Null Hypothesis Assumptions Test Statistic Effect Size Reporting Chi-Square Independence Test – What Is It? The chi-square independence test is a procedure for testing if two categorical variables are related in some population.Example: a scientist wants to know if education level and marital status are […]
SPSS Chi-Square Test Tutorials Chi-Square Independence Test – What and Why? SPSS Chi-Square Independence Test SPSS One Sample Chi-Square TesT
Do you think running a two-way ANOVA with an interaction effect is challenging? Then this is the tutorial for you. We’ll run the analysis by following a simple flowchart and we’ll explain each step in simple language. After reading it, you’ll know what to do and you’ll understand why. We’ll use depression.sav throughout. The screenshot below shows it in variable […]
Independent Samples T-Test – What Is It? Null Hypothesis Test Statistic Assumptions Statistical Significance Effect Size Independent Samples T-Test – What Is It? An independent samples t-test evaluates if 2 populations have equal means on some variable.If the population means are really equal, then the sample means will probably differ a little bit but not […]
For testing moderation effects in multiple regression, we start off with mean centering our predictors:mean centering a variable is subtracting its mean from each individual score.After doing so, a variable will have a mean of exactly zero but is not affected otherwise: its standard deviation, skewness, distributional shape and everything else all stays the same. After mean […]
Summary Creating dummy variables for several categorical variables by basic syntax is usually not hard. However, applying proper variable labels to the newly created dummy variables requires quite a bit of effort. The tool presented in this tutorial will take care of this -and some other issues- more easily. SPSS Dummy Variables Tool SPSS Create Dummy Variables Tool Instructions […]
Dummy coding a variable means representing each of its values by a separate dichotomous variable. These so-called dummy variables contain only ones and zeroes (and sometimes missing values). The figure below shows how the variable “pet” from favorite_pets.sav has been dummy coded as pet_d1 through pet_d4. Dummy Variables in SPSS Note that, for example, pet_d2 represents the value 2 on […]
Summary SPSS CORRELATIONS generates tables with Pearson correlations and their underlying N’s and p-values.* This tutorial quickly walks through its main options, using freelancers.sav for demonstrational purposes. User Missing Values Before running any correlations, we’ll first specify all values of one million dollars or more as user missing values for income_2010 through income_2014.* We’ll do so by running the following line […]
A magazine wants to improve their customer satisfaction. They surveyed some readers on their overall satisfaction as well as satisfaction with some quality aspects. Their basic question is“which aspects have most impact on customer satisfaction? ”We’ll try to answer this question with regression analysis. Overall satisfaction is our dependent variable (or criterion) and the quality […]
A magazine publisher surveyed readers on their overall satisfaction and a number of quality aspects. Their data can be downloaded from magazine.sav. Now, when working with real world data, the first thing you want to do are some basic data checks. This tutorial walks you through. The actual regression analysis on the prepared data is covered in the next […]
A company wants to know how job performance relates to IQ, motivation and social support. They collect data on 60 employees, resulting in job_performance.sav. Part of these data are shown below. Quick Data Check We usually start our analysis with a solid data inspection. Since that’s already been done for the data at hand, we’ll limit it […]
A large bank wants to gain insight into their employees’ job satisfaction. They carried out a survey, the results of which are in bank_clean.sav. The survey included some statements regarding job satisfaction, some of which are shown below. Research Question The main research question for today iswhich factors contribute (most) to overall job satisfaction?as measured by overall (“I’m […]
