3. Suppose you wish to estimate the proportion of cars that are red. Find the sample size needed to assure with 92% confidence that the sample proportion will not differ from the population proportion by more than 5%.

4. A study of 16 python snakes found the average length was 21.8 ft. Find the margin of error needed to estimate the average length of all python snakes with 90% confidence. Assume is known to be 3.1 ft.