What happens to the observations in the mydata.pay data set after the sorting operation?

When a SAS data set is sorted using a procedure like PROC SORT without the OUT= option, the data set itself is modified in place. In the case of the sorting operation performed on mydata.pay, the records are rearranged in ascending or descending order, depending on the specified sort order.

If the sorting is specifically done by the variable idNumber and in descending order, mydata.pay is indeed updated to reflect this new order. Thus, the observations will be re-created such that they are arranged in descending order based on the values of idNumber. This operation effectively overwrites the original data set with the sorted data, resulting in a clear change in the storage of the observations.

Other responses may suggest that the original order is maintained or that a new dataset is created, but these do not apply here since that behavior is contingent upon the use of the OUT= option, which is not mentioned in this context. If the OUT= option were used, then a new data set would indeed be generated, but that is not the case with the given scenario.