Question

An agricultural researcher plants 40 plots with a new variety of yellow corn. Suppose that the yield per acre for the new variety of yellow corn follows a Normal distribution with an unknown mean of μ and a standard deviation of σ = 12 bushels per acre. Which of the following would produce a confidence interval with a smaller width (or length) than the 95% confidence interval?

Plant only 10 plots rather than 40, because 10 are easier to manage and control.

Compute a 93% confidence interval rather than a 95% confidence interval, because a lower confidence level will result in a smaller width (or length).

Plant 25 plots rather than 40, because a smaller sample size will result in a smaller width (or length).

Compute a 99% confidence interval rather than a 95% confidence interval, because a higher confidence level will result in a smaller width (or length).

Answer 1

Ans:

Lower the cinfidence level,lower the margin of error,smaller the width of confidence interval.

Larger the sample size,lower the margin of error,smaller the width of confidence interval.

Correct option is:

compute a 93% confidence interval rather than a 95% confidence interval, because a lower confidence level will result in a smaller width (or length)