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- Theses, studies, program evaluations, surveys, business data.
- Rather work it out yourself? Try the test chooser below.
Interactive guide
Which statistical test should I use?
Answer a few plain-language questions. You'll get a suggested test, what to check before you trust it, and links to free tools.
A starting point, not a substitute for looking at your data. Design details such as clustering, missing data, and multiple comparisons can change the right answer.
Free resources
Free tools and guides
These live on the DASS site and are free to use.
Tools
Power analysis calculators
Plan sample size for t-tests, ANOVA, correlations, chi-square, and multilevel designs.
Open calculators →APA 7 results formatters
Turn statistical output into clean, copy-ready APA sentences. Runs in your browser.
Open formatters →Check a reported p-value
Recompute the exact p from a t, F, chi-square, or correlation statistic and compare it to what was reported.
Check a p-value →Guides
- Build a Raw-Score-to-T-Score Crosswalk for a Short Form
- Reviewer 2 Criticized Your Shortened Scale? How to Defend It
- How to Shorten a Survey Scale Without Losing Validity
- The Data Audit Checklist to Run First
- FIML vs. Multiple Imputation: Which to Use?
- When a Reviewer Challenges Your Model
- Power for Cluster-Randomized Trials Isn't Simple
- How Much Does a Statistical Consultant Cost?
Answers
Recent questions, answered
Plain-language answers to statistics questions people are asking.
Consistent vs unbiased estimators: how do they differ?
Unbiased means right on average at a fixed sample size; consistent means closing in on the truth as the sample grows. Either can hold alone.
Read the answer →How do you compare two classifiers across several datasets?
Means, win counts and the Wilcoxon signed-rank test each summarize per-dataset scores differently. Here is what each one tells you and which to report.
Read the answer →What is quantile regression and when should you use it?
Quantile regression fits a line for the median, the 90th percentile or any other quantile, so you can see how the whole distribution moves with a predictor.
Read the answer →Need more than an answer?
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