An algebra placement test was used to determine placement in mathematics courses. a sample of calculus students gave 50 scores. it is known stack sum space space with i equals 1 below and 50 on top x subscript i superscript 2 equals 20500 comma space sum from i equals 1 to 50 of space x subscript i equals 821. space use the sample standard deviation as the population deviation. if you want mu to be captured in a 96% confidence interval with length equal to 4, what is the minimum sample size?