Suppose, X16-Binom (n,e) and 8-U(0, 0.25), then Var (r) is equals to, 5n n² a) 48 192 b) Sn + 48 192 n 5n c) のの 192 48 d) 5n 48 The diameter of a ring is known to have a normal distribution with standard deviation of 0.05 inch. A random sample of 20 rings have an average diameter of 2.1015 inch. What is the 95% two-sided confidence interval for the population mean diameter of rings. (1.0781, 2.1249) (2.0781, 2.1249) (-2.0781,-2.1249) Cannot determine with the given information. XXX,be independent and identically distributed sample taken from (1). (X)-x. T(X)-(1) T(X)-Nina) (x)-() 4 T(X)-2() From the known data, there is roughly an 85% chance that a person of age 20 years will be alive at age 75 years. Suppose that 4 people of age 20 years are selected at random. What is the probability that the number alive at age 75 years will be at least 3? 0.1095 0.8905 0.3685 0.5520