error analysis
 

I have a graph of Force(mN) vs Distance(m). The error in the force is
0.0001g and the error in the distance is 0.0254mm. I have 10 points on
the graph. Excel gives R^2 = 0.90. My gradient is 1.045. What is it's
error? Can someone help?


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error analysis
 

labview1958 said the following on 3/26/2006 7:12 AM:
I have a graph of Force(mN) vs Distance(m). The error in the force is
0.0001g and the error in the distance is 0.0254mm. I have 10 points on
the graph. Excel gives R^2 = 0.90. My gradient is 1.045. What is it's
error? Can someone help?


It helps to insert the formula you are using.
Distance(m) meters? as opposed to (mm) milimeters?

error analysis
 

I have another problem about excel staight line graphs. The error bar in
the y-axis is 0.0002 and the x-axis is 0.2. Does the slope of my graph
have an error of 0.0002/0.2 = 0.001 ? Is that a fair assumption?


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error analysis
 

labview1958 said the following on 3/26/2006 10:01 AM:
I have another problem about excel staight line graphs. The error bar in
the y-axis is 0.0002 and the x-axis is 0.2. Does the slope of my graph
have an error of 0.0002/0.2 = 0.001 ? Is that a fair assumption?


I would look into one of the MVP sites on excel charting
Going through David McRitchie's site
http://www.mvps.org/dmcritchie/excel/xlindex.htm
I found these subsequent links for manipulating excel charts.
http://peltiertech.com/Excel/Charts/index.html#hdrAxes
http://www.edferrero.com/charting.aspx

error analysis
 

I have looked at the sites but I still have not found a reasonable
answer. Is my reasoning flawed?


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error analysis
 

I have come across a formula that calculates the error in a slope. Here
it is:

error in slope = (N (sigma(y) ^ 2))/(delta)

Can excel help?


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error analysis
 

labview1958 said the following on 3/27/2006 11:02 PM:
I have come across a formula that calculates the error in a slope. Here
it is:

error in slope = (N (sigma(y) ^ 2))/(delta)

Can excel help?


In Excel, I use statistical functions to determin error in slope
{=LINEST(y-range,x-range,intercept,statistics)}. Which is typed in
like this =LINEST(B6:B12,A6:A12,,1) then hit ctrl+shift+enter.
Ctrl+shift+enter will place the {} around the formula.

See MS KB at for the description and sample use. I assume you have
Excel 2003 or 2004.
http://support.microsoft.com/kb/828533

I assume you need to view a sample worksheet If you need one I can send
it to you but use an anti-virus checker.