statistics: variable cost per unit

:?
An important application of regression analysis in accounting is in the estimation of cost. By collectiong data on production volume (units) and cost and using the least squares method to develop an estimated regression equation relating production volume and cost, an accountant can estimate the cost associated with a particular production volume. Consider the following sample of production volume and total cost data for a manufacturing operation.

Production Volume Total Cost
400 4000
450 5000
550 5400
600 5900
700 6400
750 7000

a. Use these data to develop an estimated regression equation that could be used to predict the total cost for a given production volume

b. What is the variable cost per unit produced?

Can someone please help me set up b.?

What method does your book/class teach for finding the regression equation?

When you reply with that information, please also show all your steps so far. Thank you!

Eliz.

I have to find the mean of x and y. mean of x=575 mean of y-5616.67
Then xi-the mean of x and yi-the mean of y.
I then multiply these two together and get 710750.
I then do xi-mean of x and square it =93750

b1=710750/93750=7.58
bo= 5616.67-7.58(575)=1258.17

^y=1258.17 +7.58x