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All right. This spreadsheet is... this video is called reverse engineering. And were going
to see if we can reverse engineer the spreadsheet and learn from that. Let's begin by right
clicking on the graph. And when we do that we will choose select the data. And I'm going
to just move this over so you can see this. You can see a variety of series are already
here. And if you click on any one of them, let's say the variable cost rectangle, and
you want to edit it. And what happened there? Let's try that again. I must have clicked
Add. Let's click Edit. Now it shows you the series. And if you click on any of these buttons
this will, for example, show you where the name of that series is. So I'm going to see
if I can scroll down. And you can see that I've got that in the graph now. If we undo
that and we click this, this now gives the X values. So you can see the series that's
generating the X values. And likewise if you click that you can see the series that's generating
the Y values. So you can actually... Let's cancel that cause we really don't want to
change. You can actually generate every single series that's happening in the graph this
way and you can actually learn how the graph is put together by looking at these series.
Now the other thing that we can look at is these buttons. And let's right click on the
button. And you can see from the format the range goes from 0 to 60, the current value
is 34. And where is the 34 going? It's going into cell G22. So let's see if we can see
G22. That's right there. And that's the 34. So you can actually... Let's close this now.
And let's click and see if when I chh.... And you can see it's changing here. And this
one is equal to 60 plus G22. So it's changing over there as well. So you can actually figure
out what all these buttons are doing as well.
The one last thing I'm going to point out in this right engineering is that you can
figure out by looking at the formula bar up here what's happening in each cell. So this
producer surplus as an example is the difference between this revenue, which itself is the
product of the price and the quantity, and this variable cost, which is the unit cost
and the quantity. So you can figure out what's being determined in every cell in the spreadsheet.
And by doing that you actually really will understand what's happening in the spreadsheet.
So that's a different way of getting at this stuff and I think quite a useful way for learning
the underlying mathematics that's behind the economics.