The management of a brewery wanted to determine the average number of ounces of beer consumed per resident in the state of Washington. Past trends indicated that the variation in beer consumption () was 4 ounces. A 95% confidence level is required, and the error is not to exceed ± 0.5 ounces.
What sample size would you recommend?
Management wanted an estimate twice as precise as the initial precision level and an increase in the confidence to 99 percent. What sample size would you recommend?