13. An agricultural researcher studies the yield of a new variety of yellow corn. Assume that the yield per acre for the new variety of yellow corn follows a normal distribution with an unknown mean and a population standard deviation of = 10 bushels per acre. The researcher plants 36 plots.

If the average yield for these 36 plots is 150 bushels per acre, what is the 90% confidence interval for the mean yield per acre for the new variety of yellow corn? Recall that z=1.645 for 90% confidence.

This problem:

Which of the following would produce a confidence interval with a smaller margin of error than the above 90% confidence interval?

Group of answer choices

Plant 100 plots rather than 36, because a larger sample size will result in a smaller margin of error.

Plant only five plots rather than 36, because five are easier to manage and control.

Plant 10 plots rather than 36, because a smaller sample size will result in a smaller margin of error.

Compute a 99% confidence interval rather than a 90% confidence interval, because a higher confidence level will result in a smaller margin of error.