Sample Size for One-Sample t-Test

Plan how many observations you need to test whether a sample mean differs from a target value. Set the expected difference, standard deviation, alpha, and desired power, and get the sample size that keeps your test decision reliable.

Good fit when

• You benchmark a sample mean against a specification limit or target
• Data are approximately normal and measured on an interval scale
• You need to balance alpha, power, and the detectable difference

Inputs required

• Expected difference from the reference value
• Standard deviation of the measurements
• Alpha level and desired power