00:01
Trend projection means we fit a straight line, linear regression, to demand versus period, and then use it to predict period 9.
00:09
So if you're doing this by hand, then we need the sums.
00:17
We've got 8.
00:18
The sum of t is 36.
00:22
The sum of y is 87.
00:26
The sum of our t squared is 204.
00:29
And the sum of t times y is 330.
00:35
The slope is n times the sum of t times y minus the sum of the t's times the sum of the y's divided by n times the sum of the t squared minus the sum of the t squared and this is negative 1 .4643.
00:58
The intercept is going to be 10 .875 minus negative 1 .1 .9 .1 .9 .9 .9 .5 .5 .5 .5.
01:08
Negative 1 .9 .5 .5 .5 .5.
01:09
4643 times 4 .5, which is 17 .4643.
01:15
So our trend line is 17 .4643 minus 1 .4643t.
01:26
For period 9, we plug 9 in for t and we get 4 .2857.
01:38
In ph stat, that's an excel add -in, use the trend production, the trend projection linear trend tool...