Use the sample information 11formula13.mml = 40, = 4, n = 20 to calculate the following confidence intervals for assuming the sample is from a normal population. (a) 90 percent confidence. (Round your answers to 4 decimal places.) The 90% confidence interval is from_____ to _______

(b) 95 percent confidence. (Round your answers to 4 decimal places.) The 95% confidence interval is from _____to _______

(c) 99 percent confidence. (Round your answers to 4 decimal places.) The 99% confidence interval is from ________to______