# Linear Regression?

Adele69
CambridgeAAT Student Posts:

**320**
Any suggestions on a good online or book resource which covers this?

My Osbourne Financial Performance book skimmed over this - equation y = a + bx, a line on a graph, Line of Best Fit, Least Squares and mathematic formula not covered, and Budgeting just repeated the earlier content. I can calculate some of these but also get stuck on others. Usually the wording catches me out, so suggesting I don't really understand what is being asked.

My Osbourne Financial Performance book skimmed over this - equation y = a + bx, a line on a graph, Line of Best Fit, Least Squares and mathematic formula not covered, and Budgeting just repeated the earlier content. I can calculate some of these but also get stuck on others. Usually the wording catches me out, so suggesting I don't really understand what is being asked.

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## Comments

376320376Least squares regression -

To forecast sales make the dependant variable Y and the number of sales people the independent variable X.

So first, some data -

Sales units - Salespersons

236. 11

234. 12

298. 18

250. 15

246. 13

202. 10

So now you need to calculate the sum of, (I can't type the sum of character of sigma, so I'll use

to mean such, alsoEmeans power of)2So,

x 79Ey 1466ExE10832xy 19736ETo calculate B,

n = number of data sets, in this case, 6.

B=nExy - (Ex)(Ey) / nEx2 - (Ex)2 = 10.12

Now must find the average of X and Y

So, X = 13.17

Y = 244.33

A is therefore = mean of Y - B(Average of X)

A = 244.33 - 10.12(13.17) = 111.05

So the least squares of regression is

Y = 111.05 + 10.12x