Objective: Program a sequential process in VBA.

Statistical process control charts are used to help control processes $($see example in Figure $1).$ One

type of control chart is the $\stackrel{}{x}($pronounced xbar $)$ and R chart, where $\stackrel{}{x}$ is the average and R is the

range. To watch the sulfuric acid level in an etching bath in a line that makes carbon fibers,

operators take three samples a shift and the lab analyzes them to determine the concentration of

sulfuric acid. At the end of the shift the operators calculate the mean and standard deviation and

plot them on a $\stackrel{}{x}$ bar and R chart. Your boss has asked you to automate the process of calculating

$\stackrel{}{x}$ and R$.$

Figure $1.$ Unrelated example of an $\stackrel{}{x}$ and $R$ chart

Using the starter file HW$6\mathrm{.}2\_$Task$1$StarterFile.xlsm create a macro that will calculate the mean and

range of three values that are entered on the worksheet. You will have to use the definition of range

to calculate range since there is no function in Excel for range. Create a button that will launch the

macro $($a quick search will show you how to make a button$).$