plot(ohms ~ juice, xlab="Apparent juice content (%)",ylab="Resistance (ohms)", data=fruitohms)
lines(lowess(fruitohms$juice, fruitohms$ohms), lwd=2)
pause()
require(splines)
attach(fruitohms)
plot(ohms ~ juice, cex=0.8, xlab="Apparent juice content (%)",
ylab="Resistance (ohms)", type="n")
fruit.lmb4 <- lm(ohms ~ bs(juice,4))
ord <- order(juice)
lines(juice[ord], fitted(fruit.lmb4)[ord], lwd=2)
ci <- predict(fruit.lmb4, interval="confidence")
lines(juice[ord], ci[ord,"lwr"])
lines(juice[ord], ci[ord,"upr"])
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