Another thing about errors is that if you combine two (or more) values
with addition or subtraction to get a result, then the error in the
result is the sum of the errors in the two (or more) components.

However, if you combine using multiplication or division, then the
%age errors are added to give the cumulative error in the result.

Hope ths helps.

Pete

On Jul 7, 6:58*pm, cer144 wrote:
Thanks!! I'll try that, see if it's good enough for the boss lol.



"Pete_UK" wrote:
The slope of a line is given by the change in y values divided by the
change in corresponding x values, i.e.:

slope = (y2 - y1) / (x2 - x1)

where x2,y2 is at one end of the line and x1,y1 is at the other end.
In your case the errors in the y values are plus or minus 0.8, so in
the worst two cases y2 may be +0.8 with y1 being -0.8, or y2 may be
-0.8 and y1 may be +0.8, so you could work out the two extremes from
this.

Hope this helps.

Pete

On Jul 7, 5:17 pm, cer144 wrote:
Hi!
I need to find the error of the slope of the line of best fit taking into
account the error of the individual data points. I have a fixed value for the
error of the points that I have figured out independently. (It's about .8 for
every point)
I have the error bars on, but excel isn't taking the error of the points
into account when determining the error of the slope! So...how do I solve
this? I don't necessarily need an excel function to do it for me, a formula
would be fine.
Thanks!- Hide quoted text -

- Show quoted text -