j Consider the following statistics which relate to a sample of data that has been drawn from a normal distribution: x = 6.928: s = 1.151 a) Construct a 99% confidence interval for the population mean. b) Construct a 99% confidence interval for the population variance. c) Using the sample standard deviation as a proxy for the population standard deviation, determine how large the sample size would have to be in order to be able to estimate the population mean with 99% confidence with a margin of error of +0.20- d) How would your answer to part c) change if you did not have this sample of data and all you knew about the population was that the distribution ranged in value from approximately 4 to approximately 12