trendlines for two phases

  • Thread starter Thread starter Guest
  • Start date Start date
G

Guest

Hello. I am working on a line chart that shows 12 weeks of data for homework
completion. The X axis is weeks and the Y axis is rate of completion. Weeks
1-6 were baseline and data was collected for completion. Weeks 7-12 were
experimental where an intervention was used to influence homework completion.
I would like to be able to insert a trend line for weeks 1-6 and a separate
trend line for weeks 7-12 on the same graph to compare student performance.
Right now, when I right-click on a data point in my grapn to create a
trendline, I get a trendline for all 12 weeks of data. Can anyone help me
create two seperate trendlines? Thanks

Elizabeth
 
Plot the data as two seperate series. Now, the trendlines would be for
weeks 1-6 and 7-12 respectively. Using two series would also make
sense since the data represent potentially different events.

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Regards,

Tushar Mehta
www.tushar-mehta.com
Excel, PowerPoint, and VBA add-ins, tutorials
Custom MS Office productivity solutions
 
Elizabeth:

I am trying to do the same thing. Did you get this to work? I wasn't
successful plotting two sets of data on a single x-axis. The second data set
plotted from the y-intercept rather than along the end of the horizontal axis
 
Sounds like you made a Line Chart when an XY chart was needed.
Try that and let us know how it goes.
best wishes
 
I made it work. I had to create two new rows in the source spreadsheet and
include the blank cells that correspond to the x values. Now if I can just
figure out how to get a trendline for each that doesn't spread across the
entire sheet!
 
Starting with
x y z
1 5 #N/A
2 7 #N/A
3 9 #N/A
4 11 10
5 #N/A 13
6 #N/A 16
7 #N/A 19
8 #N/A 22

Select everything and make a chart
Now add the trendlines
best wishes
 
Continued:
To get partial trendline
Make a chart with the first dataset (A1:B5)
Select A5:A9; hold CTRL key and select C5:C9; click chart; use Edit |Paste
Special specifying New Series with x-values in first column
Now add the trendlines
best wishes
 
Alternatively,
Make chart from all the data (two series)
Right click chart; open Source Data dialog
Make y data series have x-values A2:A5 and y-value B2:B5
Make z data series have x-values A5:A9 and y-values C5:C9
best wishes
 
Thanks for all your input. The next hurdle is the trendline; it extends for
the full length of the x-axis. In my case this is 36 entries. This will get
messy with two data series, four trendlines, and three milestone markers.
Alternatively,I wanted to create data for the trendline (using y=mx+b), but I
don't have any 'real' x values - there just labels. I tried adding a line
graphic, but this isn't well preserved after saves or chart changes.
 
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