I need help on some questions: The first two seem really easy, but i cant seem to figure out the right approach: Marks in ECMB11 are normally distributed with a mean of 70% and standard deviation of 10%. Suppose an A is a mark of 80% or more. 1. If you take a sample of 120 students, what is the probability that at least 20 will receive an A. 2. What is the probability that average mark for 120 students will be at least 80%. ------------- You are conducting a lower tailed test. Suppose alpha = 0.10, beta = 0.01, n = 16, s = 1460, and u subscript a (i guess population of a) = 2400. Determine u subscript o. (I guess population of o) I have no idea what they are even asking for in this question HELP is greatly appreciated.