The researcher conducted a t test to compare the differences between the mean of two groups, he was uncertain about the results and repeated it.As a statistician, what advice would you give the researcher? Which of the following would be correct and why?

the significance of the t ratio is equivalent to the degrees of freedom

the smaller the t ratio, the greater the difference between the 2 groups

only conduct the t test once

the greater the difference between the 2 groups, the greater the Type I error