Excel VBA Development of a Dialog Box for the Shapiro-Wilk Test Using Royston's Algorithm

Abstract

In mathematical statistics, a significant part of the hypothesis evaluation tests can only be performed on a sample from a normally distributed population. To check normality, the most reliable Shapiro-Wilk test based on Royston's extension can be applied to both small and large samples. Since our data to be evaluated can be conveniently processed with a spreadsheet program, it is a great help for users that statistical calculations can also be performed with the spreadsheet, there is no need for statistical programs and data export for further processing. That is why it was necessary to supplement the capabilities of Microsoft Excel with a normality check. A user-friendly way of performing the calculations can be realized in a dialog window, the design of which is made possible by the Visual Basic for Applications service. An event-driven programming technique enables the creation of a program that works in harmony with the user's activity, and the design of the program's user interface. The completed program does not only support data entry by typing them in, we can also request an evaluation of the worksheet data. We can also display the results in a table on a worksheet.