Final answer:
Choose a conditional function, such as an IF statement, when you need to make a decision and return different outcomes in a problem based on a logical test.
Step-by-step explanation:
To solve the problem described, where a decision is needed and different values are generated based on a TRUE or FALSE result from a logical test, you would choose a conditional function. In programming or spreadsheet applications, this corresponds to IF statements, which are used to evaluate conditions and return different outcomes accordingly. If you are using a spreadsheet like Microsoft Excel, the IF function allows you to set a condition and then define what value should be output if the condition is true, and what value if the condition is false.