Identify the type of t-test you need: one-sample, paired, or two-sample
Use the one-sample t-value formula: t = (x̄ – μ) / (s / √n)
Use the paired t-value formula: t = d̄ / (sd / √n)
Use the two-sample t-value formula: t = (x̄1 – x̄2) / √(s1²/n1 + s2²/n2)
Compute the sample mean x̄
Compute the population mean μ or the comparison mean
Compute the sample standard deviation s
Compute the sample size n
Subtract the mean value from the sample mean
Divide by the standard error
For paired data, compute the mean of the differences d̄
For paired data, compute the standard deviation of the differences sd
For two samples, compute both sample means, both sample standard deviations, and both sample sizes
Substitute all values into the correct formula
Calculate the t value
Compare the t value with the critical t value or use the p-value for significance testing