Find a 98% confidence interval for the true difference in the two learning procedure. Advice: To get command in this topic, solve exercise on page 262-265 from question # 3 to 21. Estimating the Variance: Chi-square Distribution. If 52 is the variance of a random sample of size 1] taken from a normal population having 2 _(n ' 1J5: - the variance 02 , then X 2 1s a value of a random variable x2 having the o chhisquare distribution with z: =n - 1degree of freedom. Confidence Internal for a? If 52 is the variance of a random sample of size n from a normal population, a (1 a )100% confidence interval for o 2 is given by [n- lj|s2