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.
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, Ada's average over the three tests, rounded to one decimal place. This fills down to E6.
To begin, type it exactly:
=ROUND(AVERAGE(B2:D2),1)
| 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, Ada's average over the three tests, rounded to one decimal place. This fills down toE6. To begin, type it exactly:=ROUND(AVERAGE(B2:D2),1). -
In
F2, Ada's grade from the boundaries inH2:I5, with an approximateVLOOKUP. Lock the table. -
F3was written with an exact match and shows #N/A, because no boundary is exactly 51.3. Fix it. -
In
B8, how many students got an A. -
In
B10, write a formula usingAVERAGEIFthat gives the average mark of the students who got an A. -
The boundary case, which is the one a student will argue about. Read
=VLOOKUP(80,$H$2:$I$5,2,TRUE)and say which grade a mark of exactly 80 gets.