Q3. The average daily quotation of a product A is distributed according to N(u=200;0=6), and that of another product B according to a N(u=190;0=-5). Two independent simple random samples are extracted, one of 10 days for the first product and another of 25 for the second. (A) Find the probability that the sample average of the first sample is greater than or equal to 202.77. (b) Calculate the probability that the sample mean of sample A minus the sample mean of sample B is greater than 2.72.