confidence interval for u if the population ol 8.3 A random sample of 100 items is taken, producing a sample mean of 49. The population standard deviation is 4.49. Construct a 90% confidence interval to estimate the population mean. 8.4 A random sample of size 70 is taken from a population that has a variance of 49. The sample mean is 90.4 What is the point estimate of u? Construct a 94% confidence interval for M