Section Exercise 8-18 (Algo) Find a confidence interval for u assuming that each sample is from a normal population. (Round the value of t to 3 decimal places and your final answers to 2 decimal places.) (a) T = 26, S=5, n=9, 90 percent confidence. The 90% confidence interval is from to (b) = 46, S=7, n= 20, 99 percent confidence. The 99% confidence interval is from to (c) = 112, s= 20, n= 25, 95 percent confidence. The 95% confidence interval is from to Calculate the FPCF for each sample and population size. Can the population be considered effectively infinite in each case? (Round your answers to 4 decimal places.) FPCF Effectively infinite? (a) N = 470, n = 24 (b) N = 200, n = 24 (c) N = 1630, n = 110