T-Test Formula:
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The T-Test is a statistical test used to determine if there is a significant difference between the means of two groups. It helps researchers assess whether observed differences are real or due to random chance.
The calculator uses the T-Test formula:
Where:
Explanation: The formula calculates the t-value by comparing the difference between group means relative to the variability in the data.
Details: T-Tests are fundamental in hypothesis testing, helping determine statistical significance in experiments, clinical trials, and various research studies across different fields.
Tips: Enter the means, variances, and sample sizes for both groups. All values must be valid (sample sizes > 0, variances ≥ 0).
Q1: What does the t-value represent?
A: The t-value measures the size of the difference relative to the variation in your sample data. Larger absolute t-values indicate stronger evidence against the null hypothesis.
Q2: How do I interpret the t-value?
A: Compare the calculated t-value to critical values from the t-distribution table based on your degrees of freedom and chosen significance level (typically 0.05).
Q3: When should I use a T-Test?
A: Use T-Tests when comparing means between two groups, assuming approximately normal distribution and similar variances between groups.
Q4: What are the assumptions of the T-Test?
A: Key assumptions include normality of data, independence of observations, and homogeneity of variances (though Welch's correction can handle unequal variances).
Q5: What's the difference between one-tailed and two-tailed tests?
A: One-tailed tests check for difference in one direction only, while two-tailed tests check for any difference (both directions). Two-tailed are more common.