in some cases it may be desirable to transform a numerical variable into categories. If a variable has a skewed distribution, it may be helpful to categorize the values into quantiles. If we wish to analyze the circumstances in which a numerical outcome variable exceeds a certain value, a binary transformation may be helpful. Provide at least one real-world example on healthcare of such a numerical data attribute and explain how transformation to a nominal representation helps.

please provide full explanation and example with citations/references.