
The Shapiro-Wilk test examines if a variable is normally distributed in a population. This assumption is required by some statistical tests such as t-tests and ANOVA.
The SW-test is an alternative for the Kolmogorov-Smirnov test. This tutorial shows how to run and interpret it in SPSS.
A binomial test examines if a population percentage is equal to x.
Example: is 45% of all Amsterdam citizens currently single? Or is it a different percentage?
This simple tutorial quickly walks you through the basics.
This z-test compares separate sample proportions to a hypothesized population proportion. This tool is freely downloadable and super easy to use.
A z-test for 2 independent proportions examines if some event occurs equally often in 2 subpopulations.
Example: do equal percentages of male and female students answer some exam question correctly?
This tutorial covers examples, assumptions and formulas and presents a simple Excel tool for running z-tests the easy way.
THIS TUTORIAL HAS 7 COMMENTS:
By Monalisa on September 21st, 2018
Great help!
By Loo on September 24th, 2018
Hi Ruben, Post hoc test is available for chi square test of independence by using standard residual method, for example for a 3 by 3 chi square table. But, is it possible to do it for a 2 by 2 table?
By Ruben Geert van den Berg on September 24th, 2018
Hi Loo!
Post hoc tests examine which proportions differ if the main chi-square independence test indicates that 2 variables are associated.
For a 2 by 2 table, however, you're comparing only 2 proportions. So there's no question which proportions differ -there's only 2 of them.
On top of that, a z-test for 2 independent proportions is preferred over the chi-square test here. The significance levels are identical but the z-test provides a confidence interval of the difference too -which is very informative. For some stupid reason, it's missing from SPSS but we built a simple tool for it.
You can also inspect the (Pearson) correlation between the 2 variables. For some dumb reason it's called a phi coefficient for 2 dichotomous variables but it's technically identical to a Pearson correlation.
Last, Bonferroni corrected pairwise z-tests for larger (2 by 3, 3 by 3...) tables are often preferred over the adjusted standardized residuals. You can request the latter by adding BPROP to the CELLS subcommand as in
CROSSTABS education BY marital_status
/CELLS COUNT COLUMN BPROP
/STATISTICS CHISQ PHI.
Note that these tests only compare column (not row!) proportions.
Hope that helps!
SPSS tutorials
By Mohamed on November 10th, 2018
Hi there
What apout IRT in spss ver 15
Tell me
Thank you
By Ruben Geert van den Berg on November 10th, 2018
Hi Mohamed!
What do you mean by "IRT"? Item Response Theory? Please clarify.
Thx!
SPSS tutorials