Aldosterone is a hormone involved in maintaining fluid balance in the body. In a veterinary study, six dogs with heart failure were treated with the drug Captopril, and plasma concentrations of aldosterone were measured Before and After treatment. The researchers are interested to see if there is a difference before and after using the drug. In other words, does the drug make a difference. Run Wilcoxon's Signed-Rank Test on the paired differences in this problem.The data vectors for the Before and After are below and can be copied into R.

Before=c(749, 469, 343, 314, 286, 223);

After=c(374, 300, 146, 134, 69, 20)

(a) Get the data into R and createa vector of the differences, called d. Show me the values of the vector of differences by typing the letter d as your last command in this code chunk in your R markdown file.

(b) Check the normality of your vector d by creating a qqnorm plot with qqline and running a Shapiro test on the vector d. Do the differences appear to be normal? Is Wilcoxon's signedrank test the appropriate test to run for this data?

(c) Run Wilcoxon's signed-rank test to test to see if the there is a difference on the median plasma concentration of aldosterone before and after using Captopril. Make sure you give me your hypotheses, your test output,, and a well write conclusion for this test.