An Agricultural Company Wanted to Know If a New Insecticide

An agricultural company wanted to know if a new insecticide would increase corn yields.Eight test plots showed an average increase of 3.125 bushels per acre.The standard deviation of the increases was 2.911 bushels per acre.Determine a 90% confidence interval for the mean increase in yield. A)(1.175,3.815) B)(1.175,5.075) C)(2.435,3.815) D)(2.435,5.075) E)(-5.075,-3.815)

A coach uses a new technique in training middle distance runners.The times for 9 different athletes to run 800 metres before and after this training are shown below. Construct a 99% confidence interval for the mean difference of the "before" minus "after" times if . A)(-0.54,2.98) B)(-6.42,8.87) C)(-0.85,3.29) D)(-0.76,3.20) E)(-0.82,3.26)