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# Example calculating t statistic for a test about a mean

The lesson demonstrates conducting a t-test for a population mean with a teacher experience sample. It explains the t-statistic calculation and the p-value interpretation to test a null hypothesis. This process helps ascertain if the true mean is less than the hypothesized mean.

## Want to join the conversation?

• after finding the t value to be equal to -2.5, how do we find the p-value (i.e. probability of getting a sample with t value equal to -2.5, given the null hypothesis H0 is true)?
• Hi Sal, so my tutor says t test is used when the standard deviation is unknown and the sample size is small. But you say we use t test when sample size is large. You have me confused, also why is
P value the probability of getting a value less than 1.25? I thought it was supposed to be greater or atleast 1.25?