(Solved): Which of the following is a principal difference between a single-sample t-test and a single-sa ...

Which of the following is a principal difference between a single-sample t-test and a single-sample z-test? A. the t-test may be used only when the population variance is known B. the z-test requires the application of degrees of freedom estimates C. the t-test is not based on a normal distribution D. the t-distribution demonstrates either positive or negative skew (depending upon the directionality of the hypothesis test) E. all of the above are true F. none of the above are true