You measure the weights of a random sample of 40 male runners. The sample mean is x bar = 60 kilograms. Suppose that the standard deviation of the population known to be sd = 5kg. a) Give a 95% CI for u, the mean of the population from which the sample is drawn.b) Find a 99% CI for the mean weight u.c) Explain why the 99% CI is wider than the 95% CI. d) How many runners would need to be included in the sample to ensure that the sample mean weight is within 0.25kg of the population mean, given a 95% confidence level?

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