An Agricultural Company Wants to Know If a New Insecticide

Multiple Choice

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.

A) 23
B) 19
C) 14
D) 63
E) 39