# Excel help with error bar formula

1. Jul 31, 2004

### akatsafa

I'm trying to create error bars on excel for a regression problem, but something is not working right. I tried following my instructor's directions, but I think something is wrong with them. Here is the formula I added to the formula bar:
$b$30+$b$31*$a2+sqrt($d\$26)

b30 and b31 are my intercept + slope, a2 is my x values, and d26 is the MS residual. I should be getting an error bar above my original line, but instead I'm getting the original line. Can someone please tell me what I'm doing wrong?

Thank you.

2. Aug 2, 2004

### rattis

Is the error so small that it is no showing up against the thinkness of the line?

I usually calculate the percentage error then enter the value in the options of the graph (right click on trendline, i think)