When should I use a T-Test vs. Z-Test?

Use a **T-Test** when your sample size is small (n 30) and you know the population variance.

What does the P-Value actually mean?

The P-Value is the probability of observing your results (or more extreme) assuming the null hypothesis is true. A low p-value (< 0.05) suggests that your data provides enough evidence to reject the null hypothesis.

Can I copy-paste data from Excel?

Yes! You can copy columns of numbers from Excel or Google Sheets and paste them directly into the input fields. The tool automatically parses comma, space, or newline separated values.

T-Test Calculator

T-Test Calculator Overview

Perform Student's t-tests (paired and unpaired)

The **T-Test Calculator** is a robust statistical analysis tool designed to compare the means of two groups and determine if they are significantly different from each other. It uses the **Student's t-test** method, which is essential when sample sizes are small and population variance is unknown. ### Supported Tests - **Unpaired (Independent) T-Test**: Compares the means of two independent groups (e.g., Test Scores of Class A vs. Class B). - **Paired (Dependent) T-Test**: Compares means from the same group at different times (e.g., Blood pressure before vs. after medication). - **Welch's T-Test**: A variation of the unpaired t-test used when the two groups have unequal variances. ### Key Formulas For an independent t-test: `t = (x̄₁ - x̄₂) / √((s₁²/n₁) + (s₂²/n₂))` *Where x̄ is mean, s is standard deviation, and n is sample size.*

How to Use T-Test Calculator

**Choose Test Type**: Select 'Unpaired' for different groups or 'Paired' for before/after scenarios.
**Input Data**: Enter your datasets for Group 1 and Group 2, separated by commas (e.g., 10, 15, 12).
**Set Alpha**: The significance level (α) is typically set to 0.05 (5% risk of false positive).
**Calculate**: Click the button to generate the T-Value, Degrees of Freedom (df), and P-Value.
**Interpret**: If p < α, the difference is statistically significant.

Frequently Asked Questions

When should I use a T-Test vs. Z-Test?: Use a **T-Test** when your sample size is small (n < 30) or the population standard deviation is unknown. Use a **Z-Test** if the sample is large (n > 30) and you know the population variance.
What does the P-Value actually mean?: The P-Value is the probability of observing your results (or more extreme) assuming the null hypothesis is true. A low p-value (< 0.05) suggests that your data provides enough evidence to reject the null hypothesis.
Can I copy-paste data from Excel?: Yes! You can copy columns of numbers from Excel or Google Sheets and paste them directly into the input fields. The tool automatically parses comma, space, or newline separated values.

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