# [R] R vs. Excel (R-squared)

Lance Westerhoff lance at quantumbioinc.com
Tue Jan 24 17:50:43 CET 2006

```Hello All-

I found an inconsistency between the R-squared reported in Excel vs.
that in R, and I am wondering which (if any) may be correct and if
this is a known issue.  While it certainly wouldn't surprise me if
Excel is just flat out wrong, I just want to make sure since the R-
squared reported in R seems surprisingly high.  Please let me know if
this is the wrong list.  Thanks!

To begin, I have a set of data points in which the y is the
experimental number and x is the predicted value.  The Excel-
generated graph (complete with R^2 and trend line) is provided at
this link if you want to take a look:

As you can see, the R-squared that is reported by Excel is -0.1005.
Now when I bring the same data into R, I get an R-square of +0.9331
(see below).  Being that I am new to R and semi-new to stats, is
there a difference between "multiple R-squared" and R-squared that
perhaps I am simply interpreting this wrong, or is this a known
inconsistency between the two applications?  If so, which is
correct?  Any insight would be greatly appreciated!

======================

> # note: a is experimental and c is predicted
> summary(lm(a~c-1))

Call:
lm(formula = a ~ c - 1)

Residuals:
Min      1Q  Median      3Q     Max
-2987.6 -1126.6  -181.7   855.3  5602.8

Coefficients:
Estimate Std. Error t value Pr(>|t|)
c  0.99999    0.01402   71.33   <2e-16 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Residual standard error: 1423 on 365 degrees of freedom
Multiple R-Squared: 0.9331,	Adjusted R-squared: 0.9329
F-statistic:  5088 on 1 and 365 DF,  p-value: < 2.2e-16

> version
_
platform powerpc-apple-darwin7.9.0
arch     powerpc
os       darwin7.9.0
system   powerpc, darwin7.9.0
status
major    2
minor    2.1
year     2005
month    12
day      20
svn rev  36812
language R

======================

Thank you very much for your time!

-Lance
____________________
Lance M. Westerhoff, Ph.D.
General Manager
QuantumBio Inc.

WWW:    http://www.quantumbioinc.com
Email:    lance at quantumbioinc.com

"Safety is not the most important thing. I know this sounds like heresy,
but it is a truth that must be embraced in order to do exploration.
The most important thing is to actually go."  ~ James Cameron

```