The following data gives the average pH in rain/sleet/snow for the two-year period 2004–2005 at 20 rural sites on the U.S. West Coast. (Source: National Atmospheric Deposition Program)

(a) Box plot this data and identify any anomalous observations.

(b) Would the sample mean or the sample median be a better descriptor of typical pH values?

(c) Use the alternative method described in Section 4.7 to test the null hypothesis that the median pH is at least 5.40.

5.335 5.345 5.395 5.305 5.315 5.380 5.520 5.190 5.455 5.330 5.360 6.285 5.350 5.125 5.115 5.510 5.340 5.340 5.305 5.265 LO.1