How do I fit a line on an excel plot to a portion of the data?

[mechengstudent]

I want a best fit line to go pass through the obviously linear portion of the
data and ignore all other points, how do i do this?

 

[Andy Pope]

Hi,

Trend lines are based on all the data points in a series.
To get a trend line on a subset of data you will need to add a new series
based on only that subset.

Cheers
Andy

 

[ShaneDevenshire]

Hi,

If you want the chart to do this, then one way is to plot the "obvious
linear protion" as one series and the rest as another series and then select
the above portion and choose Chart, Add Trendline. You could also manually
calculate the trendline in the spreadsheet for the points that make up the
"obvious linear portion" using some combination of the LINEST, TREND, SLOPE
or INTERCEPT spreadsheet functions.

Then you would calculate and plot the trendline as a separate series. I
suspect you can find at least one example at Jon's website. Google Excel
Charts and look for Jon Peltier's sites.

 

[Kelly O'Day]

Here's a link to an interactive Excel regression tool that let's you select
which continuous set of data points you want to do regression on.

http://processtrends.com/toc_trend_analysis_with_Excel.htm#Interactive_Regression

Let me know if you need any further help

Kelly

http://processtrends.com