An agricultural company wants to know if a new insecticide would increase corn yields.They will use test plots to collect observations with and without the insecticide.If they want to estimate the mean increase with a margin of error of 1.2 bushels per acre,with 99% confidence,estimate the minimum number of test plots they need.A previous study showed that the standard deviation of the increases was about 2.9 bushels per acre.

Question

Quizplus · Accepted Answer

To find the minimum number of test plots, use the formula for sample size in estimating a mean: n = (Z*σ/E)^2. For 99% confidence, Z is approximately 2.576. Given σ = 2.9 and E = 1.2, n = (2.576*2.9/1.2)^2 ≈ 38.7, which rounds up to 39.

An Agricultural Company Wants to Know If a New Insecticide