Cumulative Tables and Graphs
Cumulative
Think of the word "accumulate" which means to gather together.
To have cumulative totals, add up the values as you go.
Example: Jamie has earned this much in the last 6 months:
| Month | Earned |
|---|---|
| March | $120 |
| April | $50 |
| May | $110 |
| June | $100 |
| July | $50 |
| August | $20 |
To work out the cumulative totals, just add up as you go.
The first line is easy, the total earned so far is the same as Jamie earned that month:
| Month | Earned | Cumulative |
|---|---|---|
| March | $120 | $120 |
But for April, the total earned so far is $120 + $50 = $170 :
| Month | Earned | Cumulative |
|---|---|---|
| March | $120 | $120 |
| April | $50 | $170 |
And for May we continue to add up: $170 + $110 = $280
| Month | Earned | Cumulative |
|---|---|---|
| March | $120 | $120 |
| April | $50 | $170 |
| May | $110 | $280 |
Do you see how we add this month's earnings to the previous month's cumulative total?
Here is the calculation for the rest:
- June is $280 + $100 = $380
- July is $380 + $50 = $430
- August is $430 + $20 = $450
And this is the result
| Month | Earned | Cumulative |
|---|---|---|
| March | $120 | $120 |
| April | $50 | $170 |
| May | $110 | $280 |
| June | $100 | $380 |
| July | $50 | $430 |
| August | $20 | $450 |
The last cumulative total should match the total of all earnings:
$450 is the last cumulative total ...
... it is also the total of all earnings:
$120+$50+$110+$100+$50+$20 = $450
So we got it right.
So that's how to do it, add up as you go down the list and you will have cumulative totals.
Graphs
We can make cumulative graphs, too. Just plot each cumulative total:
| Month | Earned | Cumulative |
|---|---|---|
| March | $120 | $120 |
| April | $50 | $170 |
| May | $110 | $280 |
| June | $100 | $380 |
| July | $50 | $430 |
| August | $20 | $450 |
Like this:
Cumulative Bar Graph
Or this:
Cumulative Line Graph