Topic: Length of Confidence Interval and Appropriate Sample Size

With written solution needed

1. You want to estimate the mean gasoline price within your town to the margin of error of 5 centavos. Local newspaper reports the standard deviation for gas price in the area is 25 centavos. What sample size is needed to estimate the mean gas prices at 95% confidence level? 2. Carlos wants to replicate a study where the highest lowest observed value is 13.8 while the lowest is 13.4. He wants to estimate the population mean u to the margin of error of 0.025 of its true value. Using 99% confidence level, find the sample size n that he needs