Assignment: Interval John Smith 4 years ago Calculate the 95% Z-interval or t-interval for the indicated parameter: (a) µ: X¯ = 240, s2 = 5184, n = 20 (b) µ: X¯ = 325, Ï2 = 196, n = 121 (c) p : Ëp = 0.29, n = 35