The following data gives the pH in rain/sleet/snow for 2004-05 at 20 rural sites on the US west 

coast. 

5.335

5.345

5.395

5.305

5.315

5.38

5.52

5.19

5.455

5.33

5.36

6.285

5.35

5.125

5.115

5.51

5.34

5.34

5.305

5.265

QUESTION: What test will you suggest to test whether a typical pH value is 5.4 or not? Conduct the test 

and conclude. 

(Previous question asked to create Q-Q plot to test normality assumption. Since the plot indicates departure from normality, I wanted to do Wilcoxon signed rank test to answer the above question. I'm not sure if Wilcoxon signed rank test is the correct one and if it is, I do not know how to do it on software. Please help.)