00:01
So on this problem, we have information on the income of a purchaser and the yearly purchase.
00:07
And let's look at, first of all, the conditions.
00:11
And this does appear to be linear.
00:13
And it does appear that it's evenly spread out as far as the residuals, if you think of where the line would be, evenly spread.
00:24
And so i think it is reasonable to think that the regression is a good equation to make.
00:33
So let's find that equation.
00:35
And we know that to determine the slope, we're going to take the standard deviation of the y value, which is that 253 .62, and divide that by the standard deviation of the x value, which is that 16 ,952 .50.
00:55
And we multiply that by the correlation coefficient, 0 .722.
00:59
And always remember, it's like the change in y over the change in x, so the standard deviation of y over the standard deviation of x.
01:05
So putting that into my calculator, 0 .722 times that 253 .62 divided by that 16 ,952 .50.
01:17
And so that's going to be small.
01:19
But we get that slope to be 0 .0108015714.
01:27
And again, i'm going to store that value in my calculator.
01:31
And now let's find what the y -intercept is...