A single sample t-test compares the mean (M) of a single sample of scores to a known or hypothetical population mean (µ). This means you need to input the value of your known (or hypothetical) mean and your sample scores. So, for example, if you wanted to find out whether the students from a particular fraternity study the same number of hours as the college average of 4 hours, you'd enter "4" as your population mean and your fraternity sample scores in the Sample X textbox.
Note: sample scores have to be entered either one score per line or as a comma delimited list (the calculator runs a type check on the data, and it won't work otherwise).
Remember to select significance level and whether your hypothesis is one or two-tailed.