What Is T-Test?
A one-sample t-test compares the average of a sample to a known or hypothesized value, accounting for the sample's size and variability. It answers whether an observed difference is likely real or just due to random chance. It's one of the most widely used tests in science and business for comparing averages when the true population variance isn't known.
Example
A factory expects light bulbs to last 1,000 hours on average. Testing a sample of 20 bulbs, a t-test can determine whether the sample's average lifespan is significantly different from 1,000 hours or just randomly varying.