A farmer is concerned that a change in fertilizer to an organic variant might change his crop yield. He subdivides 6 lots and uses the old fertilizer on one half of each lot and the new fertilizer on the other half. The following table shows the results.
a. Specify the competing hypotheses to determine whether the median difference between the crop yields differs from zero.
b. Calculate the value of the Wilcoxon signed-rank test statistic T. Do not assume that the sampling distribution of T is norm ally distributed.
c. At the 5% significance level, what is the decision rule?
d. Is there sufficient evidence to conclude that the median difference between the crop yields differs from zero? Should the farmer be concerned? Explain.