T-Test Calculator for 2 Independent Means
This simple t-test calculator provides full details of the t-test calculation, including sample mean, sum of squares and standard deviation.
Further Information
A t-test is used when you're looking at a numerical variable — for example, height — and then comparing the averages of two separate populations or groups (e.g., males and females).
Requirements
- Two independent samples
- Data should be normally distributed
- The two samples should have the same variance
Null Hypothesis
H₀: μ₁ - μ₂ = 0, where μ₁ is the mean of first population and μ₂ the mean of the second.
As above, the null hypothesis tends to be that there is no difference between the means of the two populations; or, more formally, that the difference is zero (so, for example, that there is no difference between the average heights of two populations of males and females).
Equation
t = (M₁ - M₂) / √[((SS₁ + SS₂) / (n₁ + n₂ - 2)) × (1/n₁ + 1/n₂)]
Where M₁ and M₂ are the sample means, SS₁ and SS₂ are the sum of squares, and n₁ and n₂ are the sample sizes.
