Answer on Statistics and Probability Question for Valerie
What is the difference between X-chart and R-chart?
The X-bar chart describes the changes of the mean or average over the time. It can be constructed by plotting an average value of each subgroup while R-chart is the range of each subgroup, i.e. subtraction of minimum value from the maximum one. Usually, these charts are represented together.
Coded-to-spec, efficient, simple and accurate.
Nice use of the named constant const double NumDays::perday = 8.0; It's a C++ naming convention to make named constants all CAPS as a signal to the reader it is non-changing, when they see it used in the code. So perday would be PERDAY.
Nice job. Clean, efficient code that compiles and runs great. You created the different classes which interacted so well