Project: A Grade Book
About this lesson
A grade book is an average rounded as a value, and a letter grade from a boundary table by approximate match. A summary block of COUNTIF and AVERAGEIF reads those two columns.
- turn marks into letter grades with a boundary table.
- summarise a class with COUNTIF, INDEX MATCH and AVERAGEIF.
The idea
A teacher's sheet, and the second project because it needs the band lookup. The average is rounded with ROUND, so the printed mark is the graded mark. The grade is a VLOOKUP with TRUE against the boundaries. The summary reads the two columns those produce.
The mistake is step 3's: an exact match against a band table, which finds nobody. The boundary table lists where each grade starts. Starts are found by approximate match, on this sheet and on every tax table and shipping-rate card there is.
The mistake to watch for
An exact match against a band table. FALSE finds only a student whose average is exactly 50, 65 or 80, and shows #N/A for everyone else. Boundaries are found with TRUE. A mark equal to a boundary belongs to the band that starts there. So round the average as a value first, so the printed mark and the graded mark agree.
Read more about this
Where this comes up again
This lesson needs JavaScript to run. Everything below is the lesson in full, but you cannot type into the grid or be marked.
In E2, type:
=ROUND(AVERAGE(B2:D2),1)
This fills down to E6.
| Row | A | B | C | D | E | F | G | H | I |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Student | Test 1 | Test 2 | Test 3 | Average | Grade | From | Grade | |
| 2 | Ada | 72 | 65 | 80 | 0 | F | |||
| 3 | Ben | 48 | 55 | 51 | 50 | C | |||
| 4 | Cai | 91 | 88 | 95 | 65 | B | |||
| 5 | Dee | 60 | 70 | 64 | 80 | A | |||
| 6 | Eli | 83 | 79 | 85 | |||||
| 7 | |||||||||
| 8 | A grades | ||||||||
| 9 | |||||||||
| 10 | A-grade average |
Every step
-
In
E2, type:=ROUND(AVERAGE(B2:D2),1). This fills down toE6. -
In
F2, find Ada's grade inH2:I5withVLOOKUP. Shape:=VLOOKUP(value, table, col, TRUE). Lock the table so it doesn't move. -
F3used an exact match and shows #N/A. No boundary equals 51.3 exactly. FixF3. -
In
B8, count the students who got an A withCOUNTIF. -
In
B10, average the marks of students who got an A withAVERAGEIF. -
This is the boundary case a student will argue about. Read
=VLOOKUP(80,$H$2:$I$5,2,TRUE)and say the grade for 80.