Basic statistical tests in a thesis: how to choose a test for your hypothesis
The names of statistical tests are easy to find, but the correct selection requires an understanding of the research question, the type of data and the structure of the study.
Key information
- ✓Start with the question and the type of variable, not the name of the test.
- ✓Distinguish between independent and repeated measurements.
- ✓Check the assumptions of the chosen method.
- ✓Report the test result together with the effect measurement and context.
First, define the purpose of the analysis.
The test can be used to compare groups, compare measurements of the same group, evaluate relationships, or analyze the breakdown of categories. The same data set can be analyzed differently depending on the question, so the goal needs to be written in one precise sentence.
Type of variable and sample arrangement
Check whether the variables are nominal, orderly or quantitative, and whether the groups are independent. Before and after the study, there are dependent measurements, but comparing two separate groups usually means independent trials.
Examples of test families
The t-test and the ANOVA are used to make specific comparisons of averages with satisfied assumptions. Mann-Whitney and other ranking methods are used as alternatives in the relevant systems. The Chi-square analyzes the relationships between categories, and Pearson or Spearman describe the relationship between two variables.
Assumptions and reporting
Before interpreting, check the data gaps, deviations, breakdowns and other assumptions of a particular test. In the text, state the method name, statistical value, degrees of freedom, p-level and measure of effect size, if applicable. The numerical result must then be referred to the research hypothesis.
Summary
Test selection is the last part of the decision-making chain, starting with the problem and the measurement method. Before the calculations, you have to identify variables, group order, assumptions, and accurately record the statistical hypothesis.
Frequently asked questions
Will the statistical program itself choose the right test?
No, the program will perform the calculated calculations, but it will not evaluate for you the meaning of the hypothesis, the quality of the measurement, or the conformity of the method to the test design.
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