Suppose you conduct a hypothesis test about a population mean when the standard deviation is unknown by calculating a t statistic and determining whether to reject the null hypothesis. Assume that your t statistic is a positive value and that you will reject the null hypothesis when t is very large. For each of the potential changes to the components of your study design or the results listed below, determine the change to the t statistic, and then select "increase," "Decreases," or "Stays the same" from the dropdown menu in the right-hand column.

A decrease in the obtained difference (M - )

An increase in the sample size (n)

A switch from using a two-tailed test to a one-tailed test

A decrease in the sample variance (s)