Let's start with t tests. A sample t test gives you a leverage point to check whether the sample mean that can have a normally distributed variable has a significant difference from the hypothesis value. For example, you need to test whether the fridge sales average is significantly different from 10000. Here is the command to run the t test:

ttest fridge_sales = 10000

This command checks whether the mean or average of fridge_sales differs significantly from 10000. Here is the exact formula for a sample t test:

Here are the results of One-sample t test as per the command that's run in Stata:

This result shows that there is a statistically significant difference between the mean values of fridge_sales and 10000. Let's see whether you have more than one group to compare the means. In this case, you can use two independent sample t-tests.