Refer to Exercise 8.28.
a. Compare the mean yields of herbicide 1 and herbicide 2 to the control treatment. Use a Â .05.
b. Should the procedure you used in part (a) be a one-sided or a two-sided procedure?
c. Interpret your findings in part (a).
The Agricultural Experiment Station of a university tested two different herbicides and their effects on crop yield. From 90 acres set aside for the experiment, the station used herbicide 1 on a random sample of 30 acres and herbicide 2 on a second random sample of 30 acres; they used the remaining 30 acres as a control. At the end of the growing season, the yields (in bushels per acre) were as follows:
a. Use these data to conduct a one-way analysis of variance to test whether there is a difference in the mean yields. Use a Â .05.
b. Construct 95% confidence intervals on the mean yields i.
c. Which of the mean yields appear to be different from the control?