Activity 16 Normal Distribution 5 Confidence Interval a process is known to produce bricks whose weights are normally distributed with a standard deviation 0.12 pounds. A random sample of sixteen bricks from today's output had a mean weight of 4.0? pounds. a. Find a 90% confidence interval for the mean weight of all bricks produced todav. b. Find a 99% confidence interval for the mean weight of all bricks produced today. c. Find the sample size needed so that a 95% confidence interval for the population mean weight of bricks extends an amount 0.01 on each side of the sample mean