Referring to Exercise 8.12b (page 309), assume that s equals .66. How large a sample of late replacement buyers is needed to make us:
a. 99 percent confident that x, the sample mean number of dealers visited, is within a margin of error of .04 of m, the population mean number of dealers visited?
b. 99.73 percent confident that x is within a margin of error of .05 of m?
2. Referring to Exercise 8.21 (page 317), regard the sample of five trial runs for which s = 19.65 as a preliminary sample. Determine the number of trial runs of the chemical process needed to make us:
a. 95 percent confident that x, the sample mean hourly yield, is within a margin of error of eight pounds of the population mean hourly yield m when catalyst XA-100 is used.
b. 99 percent confident that x is within a margin of error of five pounds of m. DS ChemYield
Text Book: Business Statics in Practice By BOWERMAN.