Question 19 5 pts A sample is selected from a population with u = 70, and a treatment is administered to the sample. After treatment, the sample mean is M = 74, and Cohen's d is d = 1.00. What is the value of the sample variance? O $2 - 4 O s2 - 16 It is impossible to determine the sample variance without more information. O s 2 = 2 Question 20 5 pts Which of the following is a fundamental difference between the t statistic and a z-score? The t statistic uses the sample mean in place of the population mean. The t statistic uses the sample variance in place of the population variance. O All of these are differences between t and z. The t statistic computes the standard error by dividing the standard deviation by n - 1 instead of dividing by n