r - Superscript a legend in plot() and add the adjusted R2 from lm() -

how can superscript 2 in "adjusted r2 = " , import value summary()?

as example:

#multiple linear regression model nitrate<-sswells[,6] predictors<-sswells[,9:31] linear<-lm(nitrate~.,data=predictors) summary(linear)  #obs vs. predicted obs <-nitrate pred <-linear$fitted.values obs.pred <- lm(obs~pred) plot(obs~pred, main="observed vs. predicted \nmultiple linear  regression", xlim=c(0,14), ylim=c(0,14), ylab="predicted nitrate [mg l-1  no3-n]", xlab="observed nitrate [mg l-1 no3-n]") abline(obs.pred) 

through searching, found that:

lgd <- bquote(r^2 == .(round(summary(obs.pred)$r.squared,3))) legend("bottomright", legend=lgd) 

gives me legend 2 in r2 superscripted, when modify to:

lgd <- bquote("adjusted" r^2 == .(round(summary(obs.pred)$adj.r.squared,3))) legend("bottomright", legend=lgd) 

so can adjusted r2 new value error

error: unexpected symbol in "lgd <- bquote("adjusted" r" 

i've tried taking quotes out around adjusted, doesn't work. i've tried putting single quote in front of it, doesn't work. i've read file , examples , can't figure out.

so tried:

text(2,12,expression(paste("adjusted ", r^2, " =", sep = ""))) 

this works, except can't figure out how import adjusted r2 summary(obs.pred)$adj.r.squared go on =, if do:

text(2,12,expression(paste("adjusted ", r^2, " =",  round(summary(actpred)$r.squared,3), sep = ""))) 

it prints text instead of actual value.

is there simple way to i'm missing?

i agree @jruf003,

lgd <- bquote(adjusted~r^2 == .(round(summary(obs.pred)$r.squared,3)))

note : don't quote "adjusted" in bquote(...) expression

then, can add in main title of plot plot(1:10, main=lgd)

output :