1. The t-formula is commonly used in statistics to calculate the t-statistic for hypothesis testing or confidence intervals. 2. The general formula for the t-statistic is: $$t = \frac{\bar{x} - \mu}{s / \sqrt{n}}$$ where: - $\bar{x}$ is the sample mean, - $\mu$ is the population mean under the null hypothesis, - $s$ is the sample standard deviation, - $n$ is the sample size. 3. To use the t-formula, you need the sample data to calculate $\bar{x}$ and $s$, the hypothesized population mean $\mu$, and the sample size $n$. 4. Substitute these values into the formula to compute the t-statistic. 5. This t-statistic can then be compared to critical values from the t-distribution with $n-1$ degrees of freedom to make inferences about the population mean. If you provide specific values or a problem, I can demonstrate the calculation step-by-step.