A single sample t-test (or one sample t-test) is used to compare the mean of a single sample of scores to a known or hypothetical population mean. So, for example, it could be used to determine whether the mean diastolic blood pressure of a particular group differs from 85, a value determined by a previous study.

*Requirements*

- The data is normally distributed
- Scale of measurement should be interval or ratio
- A randomized sample from a defined population

*Null Hypothesis*

H_{0}: *M* - *μ* = 0, where M is the sample mean and μ
is the population or hypothesized mean.

As above, the null hypothesis is that there is no difference between the sample mean and the known or hypothesized population mean.

*Equation*