Question: Comparing voltage readings. A Harris Corporation/University of Florida study was undertaken to determine whether a manufacturing process performed at a remote location could be established locally. Test devices (pilots) were setup at both the old and new locations, and voltage readings on the process were obtained. A ‘‘good'' process was considered to be one with voltage readings of at least 9.2 volts (with larger readings better than smaller readings). The first table on p. 18 contains voltage readings for 30 production runs at each location.

(a) Construct a relative frequency histogram for the voltage readings of the old process.

(b) Construct a stem-and-leaf display for the voltage readings of the old process. Which of the two graphs in parts a and b is more informative?

(c) Construct a frequency histogram for the voltage readings of the new process.

(d) Compare the two graphs in parts a and c. (You may want to draw the two histograms on the same graph.) Does it appear that the manufacturing process can be established locally (i.e., is the new process as good as or better than the old)?