The article "Ozone for Removal of Acute Toxicity from Logyard Run-off" (M. Zenaitis and S. Duff, Ozone Science and Engineering, 2002: 83-90) presents chemical analyses of runoff water from sawmills in British Columbia. Included were measurements of pH for six water specimens: 5.9, 5.0, 6.5, 5.6, 5.9, 6.5. Assume that these are a random sample of water specimens from a normal population. These data also appear in Exercise 5 in Section 5.3.
a. Find a 98% prediction interval for a pH of a single specimen.
b. Find a tolerance interval for the pH that includes 95% of the specimens with 95% confidence?