The sample coefficient of variation (CV) is a measure of relative variability and it is useful when evaluating the performance of a workstation. The CV, the sample average (x), the sample standard deviation (s) of the total assembly time of a job at a workstation is based on a sample of n observed assembly times (x1, x2, X3,..., xn). The formula to estimate the CV is: Sample Standard Deviation Sample Average Where: CV s= 21x7 - n-1 n ; CV <0.75 0.75 ≤CV ≤ 1.33 CV > 1.33 S X Σ₁=1*1 n X=- The relative variability experienced by the workstation is based on the value of the calculated CV (see Table 1). Table 1. Type of relative variability based on the value of CV Value of CV Type of Relative Variability Low Medium High Programming suggestion: If you are getting stuck on something, make an assumption in your code and work from that. For example, if you aren't sure how to check if your input is valid, assume the entry is valid, write all your code with that assumption. Then come back to trying ways to check the input. Problem 1 (5 pts) 1. Write a VBA program to calculate and return to the user the sample average (x), the sample standard deviation (s), the sample coefficient of variation (CV), and the relative variability (from table 1) of the total assembly time of a job at a workstation based on a sample of n observed assembly times (x1, X2, X3,... Xn).: Your program must read in the individual observed assembly times from the spreadsheet and use VBA to do all the calculations. All values reported in the spreadsheet need to be values, not formulas. • Check that the assembly times entered are valid entries. Where there are invalid entries, inform the user and ask them to retry. • Develop a user interface that instructs the user how to interact with the program. An example of an interface is shown in Figure 1 on the next page. • Your program code must output the summary including the formatting ● Use a main sub procedure and all other functions/sub procedures will run from that. o No individual function/sub procedure can be longer than ~30 lines of code (don't count white space and comment lines).