(Original post by aznkid66)
As you can see, I kinda omitted the part about finding the slope with a graph. You need to understand that the slope is ∆y/∆x, which really isn't a graphical interpretation at all. If you're getting the reciprocal, you might be doing ∆x/∆y. Think of slope as how much 'y' changes after a unit change (of 1) in 'x'.
For example, if you have the equation y=7x, then you can pick any two 'x' values with a difference of 1 (e.g., 0 to 1, 2 to 3, 3 to 4) and observe that the difference in 'y' (e.g., 0 to 7, 14 to 21, 21 to 28). is constant (7).
And one more question to solve / confirm. Here's the question:
Q6 The revenue R (£’000) of a manufacturing process is given by the equation R = 300x – 4x^2
where x is the quantity of manufactured products sold in ’00 units. The production cost
C (£’000) of the same manufacturing process is given by the equation C = 2400 + 40x,
where x is the quantity of manufactured products produced in ’00 units.
(a) Construct a table to calculate the value of C and R, using the values 0, 5, 10, 15, 20,
25, 30 and 35 for x. (4 marks)
(b) Use the values of C and R calculated in (a) to plot a fully labelled graph for C and R
against x. (6 marks)
(c) Use the graph drawn in (b) to estimate the quantity of manufactured products where
the manufacturing process breaks even (i.e. where neither a profit nor loss is made). (2 marks)
So, as you can see in the attached picture (in png format), the answers for (a) I think are right. Please confirm
And another thing - part (b) drawn and attached in the jpg format; however, although I've drawn the graph very accurately, and, I'm surprised, that I only made use of 1 or 2 points on the revenue line from the above table but yet I managed to draw the line but then part (c), my answer being 1700 units, is wrong yet the graph of part (b) shows that's the answer and the graph is drawn as accurately as possible. So what is the right answer? Can anyone help me?
Well, measure of dispersion means how "spread out" the data is. I know two terms that, by their definitions, measure spread (but then again, I may be using "spread" wrongly).
Edit: Interquartile range is one, too.
However, even after finding how "spread out" a set of data is, you still don't know what point(s) the set is spread out from. For example, if you graphed the data, moving all the points up/down and left/right will change the measure of location, but will not change the measure of dispersion. I hope you can, with these hints, deduce what the measure(s) of location are (hint: 3 Ms).