Excel's Formula - sisman

Chapter 8: Using Lookup Functions 225
without using a lookup table. Rather, the information in the lookup table is hard-coded into an
array constant. See Chapter 14 for more information about array constants.
=VLOOKUP(B2,{0,”F”;40,”D”;70,”C”;80,”B”;90,”A”},2)
Another approach, which uses a more legible formula, is to use the LOOKUP function with two
array arguments:
=LOOKUP(B2,{0,40,70,80,90},{“F”,”D”,”C”,”B”,”A”})
Finally, whenever you can easily convert your input, the number grade in this case, into the integers
1 to 254, the CHOOSE function becomes an option. The number grades are divided by 10,
the decimal is stripped off, and 1 is added to it to produce the numbers 1 to 11. The remaining
arguments define the return values for those 11 options.
=CHOOSE(TRUNC(B2/10)+1,”F”,”F”,”F”,”F”,”D”,”D”,”D”,”C”,”B”,”A”,”A”)
Calculating a grade point average
A student’s grade point average (GPA) is a numerical measure of the average grade received for
classes taken. This discussion assumes a letter grade system, in which each letter grade is
assigned a numeric value (A=4, B=3, C=2, D=1, and F=0). The GPA comprises an average of the
numeric grade values, weighted by the credit hours of the course. A one-hour course, for example,
receives less weight than a three-hour course. The GPA ranges from 0 (all Fs) to 4.00
(all As).
Figure 8-11 shows a worksheet with information for a student. This student took five courses, for
a total of 13 credit hours. Range B2:B6 is named CreditHours. The grades for each course appear
in column C (Range C2:C6 is named Grades). Column D uses a lookup formula to calculate the
grade value for each course. The lookup formula in cell D2, for example, follows. This formula
uses the lookup table in G2:H6 (named GradeTable).
=VLOOKUP(C2,GradeTable,2,FALSE)
Figure 8-11: Using multiple formulas to calculate a GPA.