Sample Size Estimator

When to use it

Use this tool before collecting data to plan sample size, precision, allocation, or detectable effects.
Use it only when the selected variables and study design match the method's requirements.

How to use it

1. Open the tool from the Quantly Tools panel.
2. Confirm the active dataset and analysis session.
3. Set Effect Size (e.g., Cohen's d, f, or w) (Required): Standardized effect size. T-Test (d): 0.2, 0.5, 0.8. ANOVA (f): 0.1, 0.25, 0.4. Chi-Square (w): 0.1, 0.3, 0.5.
4. Set Statistical Power (1 - β) (Required): The probability of finding an effect if it exists. Typically 0.80 or higher.
5. Set Significance Level (α) (Required): The probability of a Type I error (false positive).
6. Set Test Type (Required): The type of t-test you plan to use.
7. Set Number of Groups (for ANOVA) (Optional): The total number of groups in your ANOVA design (e.g., 3).
8. Set Number of Rows (for Chi-Square) (Optional): The number of categories in the first variable for the Chi-Square test.
9. Set Number of Columns (for Chi-Square) (Optional): The number of categories in the second variable for the Chi-Square test.
10. Set Plot Multiple Effect Sizes (Optional): Show power curves for small, medium, and large effect sizes for comparison.
11. Review optional or advanced settings and keep defaults unless your design requires a change.
12. Run the tool, inspect warnings and diagnostics, then save or export the result with its assumptions.