Final answer:
A nested IFTHENELSE function involves placing one IFTHENELSE inside another to evaluate multiple conditions. For instance, in determining grades, you can nest functions to check for different thresholds of a student's average and assign a corresponding letter grade.
Step-by-step explanation:
To write a nested IFTHENELSE function, you insert one IFTHENELSE function inside another. This allows you to evaluate multiple conditions in a sequence. For example, consider the following scenario: you need to determine a student's final grade based on a series of conditions. Here's how you could structure a nested IFTHENELSE:
IF the student's average is above 90, THEN they get an 'A'; ELSE, check if the average is above 80. IF it is, then they get a 'B', ELSE check if the average is above 70, and so on.
Here is a simplified code example:
IFTHENELSE(average > 90, 'A', IFTHENELSE(average > 80, 'B', IFTHENELSE(average > 70, 'C', 'F')))
This nested function first checks if the average is over 90. If that condition is true, it returns 'A'. If not, it moves to the next condition and continues until it finds a true condition or reaches the final ELSE segment.