T-Tests
Compare means between groups
T-Tests
T-tests compare means between groups to determine if differences are statistically significant.
Types of T-Tests
Independent Samples T-Test
Compare means between two separate groups.
Example: Compare test scores between students in different schools.
Data Requirements:
- Data Column: Numeric variable to compare
- Group Column: Categorical variable with exactly 2 groups
- Sample Size: At least 2 observations per group
Paired Samples T-Test
Compare means of related observations.
Example: Before/after treatment measurements.
Data Requirements:
- Column 1: First set of measurements
- Column 2: Second set of measurements (paired)
- Sample Size: At least 2 pairs
One-Sample T-Test
Test if a single group differs from a hypothesized value.
Example: Test if a class average differs from the national average.
Data Requirements:
- Column: Numeric variable
- Population Mean: Hypothesized value (default: 0)
- Sample Size: At least 2 observations
How to Run
- Select “T-Test” from the test dropdown
- Choose the test type (Independent, Paired, One-sample)
- Select your data columns
- Click “Run Test”
Interpreting Results
Key Statistics
- t-statistic: Measure of difference relative to variability
- p-value: Probability of observing this difference by chance
- Degrees of Freedom: Number of independent observations
- Group Means: Average values for each group
Statistical Significance
- p < 0.05: Generally significant
- p < 0.01: Strong significance
- p < 0.001: Very strong significance
Assumptions
- Normality: Data approximately follows normal distribution
- Independence: Observations are independent (except paired tests)
- Equal Variance: Groups have similar variability (independent tests)
Export Options
- LaTeX: Copy-paste ready tables
- CSV: Structured data files
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