Reference no: EM1316480

To test whether there is significant difference between two proportions.

The Damon family owns a large grape vineyard in western New York along Lake Erie.  The grapevines must be sprayed at the beginning of the growing season to protect against various insects and diseases.  Two new insecticides have just been marketed:  Period 5 and Action.  To test their effectiveness, three long rows were selected and sprayed with Period 5, and three others were sprayed with Action.  When the grapes ripened, 400 of the vines treated with Period 5 were checked for infestation.  Likewise, a sample of 400 vines sprayed with Action was checked.  The results were:

Insecticide	Number vines checked (sample size)	#of infested vines
Period 5	400	24
Action	400	40

At the .05 level of significance, can we conclude that there is a difference in the proportion of vines infested using Period 5 as opposed to Action?

This is a two-sample test involving proportions instead of means.

Required:

• Is there any difference in sampling theory as it applies to tests of sample means vs. tests of sample proportions?  Discuss.
• Show all 5 steps to test the above problem.

Spend time on your conclusion -- state whether you reject the null or you do not reject it (fail to reject) and then discuss what this conclusion means as it relates to this particular problem.