Summarize the issue and provide insights on improving the outcomes of the following case:

Jared Beane, an analyst at a research firm, prepares to write a report on the new ultra-green car that boasts an average of 100 mpg. Based on a sample of 25 cars, Jared reports, with 90% confidence, that the average mpg of all ultra-green cars is between 92.86 mpg and 100.18 mpg. Jared also constructs the 90% confidence interval for the proportion of cars that obtain more than 100 mpg and reports the interval between 0.132 and 0.428. Jared wishes to increase the precision of his confidence intervals by reducing the margin of error. If his desired margin of error is 2 mpg for the population mean, he must use a sample of at least 75 cars for the analysis. Jared also wants to reduce the margin of error to 0.10 for the proportion of cars that obtain more than 100 mpg. Using a conservative estimate, he calculates that a sample of at least 68 cars is needed to achieve this goal. Thus, in order to gain precision in the interval estimate for both the mean and the proportion with 90% confidence, Jared's sample must contain at least 75 cars