Trendline Question

[Bill Helbron]

I have a chart with a trendline but I've noticed that the trendline line doesn't
seem to change much, if at all! I was wondering if, once I enter new data and
save the file, does the trendline automatically update or do you have to do
something else to get it to update?

Bill

 

[robert111]

Have you calculated the trend parameters yourself using slope and
intercept functions? If so check your formula ranges are big enough to
capture new data.

 

[Bill Helbron]

My chart is a scatter plot of values (Y) vs. date (X). So, to answer your
question, no, since I don't know how to handle dates in the function
calculation. As far as the "ranges" being "big enough", how do I check this?

Bill

 

[robert111]

you can subtract one date from another so you can create a new row of
values for the slope and trend calculations

1 jan 8 jan 15 jan
1 7 1