D 10 2 10 1 5) A random sample of 225 observations were selected from a population with a mean / = 20 and variance oz = 144. Find mean and standard deviation of the sampling distribution of the sample mean. O mean = 20, s.d. = 12 O mean = 20, s.d. = 0.64 O mean = 20, s.d. = 0.8 O mean = 0.9, s.d. = 12 O mean = 0.9, s.d. = 0.8 D 10] Ra 11 1 5) According to American Automobile Association, the average cost of a gallon of regular unleaded fuel at gas stations in May 2014 was.$3.65. Assume that the standard deviation of such cost is $0.25. Suppose that a random sample of n=100 gas stations is selected from the population and the cost per gallon of regular unleaded fuel is determined for each. What is the approximate probability that the sample has a mean fuel cost between $3.60 and $3.70? 0 1 O 0.1586 O 0.9544 O 0.9772 D 10 12 1 5 ) A random sample of 100 observations, Denote by X1, X2, ..., X100, were selected from a population with a mean u = 40 and variance o = 400. Determine P(38