2. What do you know about the distribution of X when X has mean / and standard deviation o ? a) If X is a random variable with a normal distribution, then the distribution of many sample means, X , is: * ~ b) If X is any random variable (regardless of Normal or skewed) and the sample size, n is large, then the approximate distribution of the sample means, X , is: X ~ c) What is the name of the formal statement of the same result in a) and b) above? 3. What are the formulae for a 100(1 - a)% confidence interval (and clearly define all the symbols used) for: a) a population mean when the population standard deviation, o, known? b) a population mean when o unknown? c) the difference between two independent population means with both o unknown