Chapter 3, Problem 15E

Consider the viscosity data in Exercise 3.10. Construct a normal probability plot, a lognormal probability plot, and a Weibull probability plot for these data. Based on the plots, which distribution seems to be the best model for the viscosity data?

3.10 An article in Quality Engineering (Vol. 4, 1992 pp. 487–495) presents viscosity data from a batch chemical process. A sample of these data is presented in Table 3E.3 (read down, then across).

1. (a) Construct a stem-and-leaf display for the viscosity data.
2. (b) Construct a frequency distribution and histogram.
3. (c) Convert the stem-and-leaf plot. Use this graph to assist in locating the median and the upper and lower quartiles of the viscosity data.
4. (d) What are the tenth and ninetieth percentiles of viscosity?

TABLE 3E.3 Viscosity