Trendline Percent

[rml]

I created a chart with a trendline. How can I figure out the percent of
increase from the formula generated from trendline?

y = 2.1973x + 3211.2
R² = 0.0046

Thanks!

 

[Bernard Liengme]

With an R² value that low, I would not trust any derived data.
best wishes

 

[rml]

It should be a small increase of say 2% or so. Anyways, how would I convert
those equations to a percent?

Thanks.

 

[David Biddulph]

The percentage increase in Y depends on your X values.
=2.1973*(X_new-X_old)/(2.1973*X_old + 3211.2) and format as percentage.

 

[Shane Devenshire]

Hi,

Since this is a linear equation, the delta Y/delta X is the same regardless
of the x position. Here is the basic idea

=(Y2-Y1)/(X2-X1)

Since you can use any values I chose 1 and 2 as my X positions and
substituted in you other numbers:

=((2.1973*2+3211.1)-(2.1973*1+3211.1))/(2-1)

the answer is 2.1973

However, as Bernard said an R squared value of 0.0046 basically means the
trend line Excel found does not match the data at all. Most likely this is
because the data is not linear, so you should test the other types of
trendlines.

 

[David Biddulph]

When the OP asked for "percent of increase", I assumed that he was asking
not for the slope =(Y2-Y1)/(X2-X1) but for the increase as a percentage of
the original value =(Y2-Y1)/Y1. In each case, of course, the answer would
need to be expressed as a percentage. My interpretation may be supported by
the fact that the OP said he was expecting about 2%, whereas Shane's formula
gives 219.73%.