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#1
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How can I get the average of curves on a plot?
Hello! I would like to get the average curve from several curves on a plot. Is there a way to do this in Excel? (Background infromation: I have, say, 10 sets of XY points and I want to take the average of these to obtain a set of average X and Y points and plot them. However, each of these 10 sets have a different amount of XY points and I can't simply take the average across the row. Any solutions?) Thanks! -- jessie joe ------------------------------------------------------------------------ jessie joe's Profile: http://www.excelforum.com/member.php...o&userid=36054 View this thread: http://www.excelforum.com/showthread...hreadid=558432 |
#2
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How can I get the average of curves on a plot?
(A) If the X-values are the same for each series the Y-value of the average
is simply the average of the respective y-values. (B) So, I assume yr X-values are not equal, though within a comparable scale. You cld try to interpolate / extrapolate the xy-pairs to obtain a kind of best-fit curve, with Add Trendline you can choose a polynomial fit which gives you say 10 estimated curves. Now the one y'r looking for is the average of Y-values belonging to that fit, identical as in (A). HTH, Henk "jessie joe" wrote: Hello! I would like to get the average curve from several curves on a plot. Is there a way to do this in Excel? (Background infromation: I have, say, 10 sets of XY points and I want to take the average of these to obtain a set of average X and Y points and plot them. However, each of these 10 sets have a different amount of XY points and I can't simply take the average across the row. Any solutions?) Thanks! -- jessie joe ------------------------------------------------------------------------ jessie joe's Profile: http://www.excelforum.com/member.php...o&userid=36054 View this thread: http://www.excelforum.com/showthread...hreadid=558432 |
#3
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How can I get the average of curves on a plot?
I am not sure I understand. How do I get the set of average X and Y values from the 10 estimated curves? -- jessie joe ------------------------------------------------------------------------ jessie joe's Profile: http://www.excelforum.com/member.php...o&userid=36054 View this thread: http://www.excelforum.com/showthread...hreadid=558432 |
#4
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How can I get the average of curves on a plot?
1) Fit each of the 10 data sets to a suitable curve (polynomial or other). Use LINEST or chart trendlines. 2) You can then take an average of the 10 curves by selecting a value for x, calculating the value for y at each of the 10 curves, then average that set of y's. This will give you an average value for y at a given x. Repeat for as many x's as needed. -- MrShorty ------------------------------------------------------------------------ MrShorty's Profile: http://www.excelforum.com/member.php...o&userid=22181 View this thread: http://www.excelforum.com/showthread...hreadid=558432 |
#5
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How can I get the average of curves on a plot?
If your data is noisy, then fitting a polynomial (as others suggested) can
smooth it before you average. However, if the data is not noisy and not from a low order polynomial, you should be aware that a least squares fit need not pass through any observed points. If you really want to average what the chart displays, then the chart smoother appears to fit Bezier curves http://www.xlrotor.com/Smooth_curve_...ample_file.zip which in most instances is not greatly different than cubic splines http://groups.google.com/group/micro...2966520eccdb1f (local polynomial fits that do pass through the data points, as opposed to a global polynomial fit that may not). Jerry "jessie joe" wrote: Hello! I would like to get the average curve from several curves on a plot. Is there a way to do this in Excel? (Background infromation: I have, say, 10 sets of XY points and I want to take the average of these to obtain a set of average X and Y points and plot them. However, each of these 10 sets have a different amount of XY points and I can't simply take the average across the row. Any solutions?) Thanks! -- jessie joe ------------------------------------------------------------------------ jessie joe's Profile: http://www.excelforum.com/member.php...o&userid=36054 View this thread: http://www.excelforum.com/showthread...hreadid=558432 |
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