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 4E.2. (read down, then across).

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

13.3 14.9 15.8 16.0 14.5 13.7 13.7 14.9 15.3 15.2 15.1 13.6 15.3 14.5 13.4 15.3 14.3 15.3 14.1 14.3 14.8 15.6 14.8 15.6 15.2 15.8 14.3 16.1 14.5 13.3 14.3 13.9 14.6 14.1 16.4 15.2 14.1 15.4 16.9 14.4 14.3 15.2 14.2 14.0 16.1 15.2 6.9 14.4 13.1 15.9 14.9 13.7 15.5 16.5 15.2 13.8 12.6 14.8 14.4 15.6 14.6 15.1 15.2 14.5 14.3 17.0 14.6 12.8 15.4 14.9 16.4 16.1 15.2 14.8 14.2 16.6 16.8 14.0 15.7 15.6