Bushels of Corn

Crop researchers plant 15 plots with a new variety of corn. The yields in bushels per acre are:

Assume that the standard deviation of the population is known to be σ = 10 bushels per acre

QUESTIONS:

1. What is  x the standard deviation of \(\bar{X}\) ?
2. Find the 90%, 95%, and 99% confidence interval for the mean yield for this variety of corn.
3. How do the margin of error in #2 change as the confidence level increases?

Now suppose that the crop researchers obtained the same value of from a sample of 60 plots rather than 15.

1. What is  x  Compute the 95% confidence interval for the mean yield 
2. Is the margin of error larger or smaller than the margin of error found for the sample of 15 plots? Explain in ONE SENTENCE why the change occurs.
3. Will the 90% and 99% intervals for a sample of size 60 be wider or narrower than those for n = 15?
4. How large a sample is required to estimate the mean yield within ±4 bushels per acre with 90% confidence?

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Solution: The downloadable solution consists of 5 pages, 371 words and 10 charts.
Deliverable: Word Document