| xmp10.05 {Devore5} | R Documentation |
The xmp10.05 data frame has 20 rows and 2 columns of data from
an experiment on the effect of alcohol on REM sleep time
This data frame contains the following columns:
Devore, J. L. (2000) Probability and Statistics for Engineering and the Sciences (5th ed), Duxbury
(1978), ``Relationship of ethanol blood level to REM and non-REM sleep time and distribution in the rat'', Life Sciences, 839-846.
data(xmp10.05)
plot(REMtime ~ ethanol, data = xmp10.05,
xlab = "Ethanol concentration administered (g/kg)",
ylab = "Amount of REM sleep during a 24 hour period")
fm1 <- lm(REMtime ~ factor(ethanol), data = xmp10.05)
anova(fm1) # compare with Table 10.4, p. 417
summary(fm1) # differences with baseline (0 g/kg)
## more appropriate to use an ordered factor
fm2 <- lm(REMtime ~ ordered(ethanol), data = xmp10.05)
anova(fm2) # same as above
summary(fm2) # polynomial contrasts
## best model uses square root of ethanol concentration
plot(REMtime ~ sqrt(ethanol), data = xmp10.05,
xlab = expression(sqrt(
plain("Ethanol concentration administered (g/kg)"))),
ylab = "Amount of REM sleep during a 24 hour period")
fm3 <- lm(REMtime ~ sqrt(ethanol), data = xmp10.05)
summary(fm3)
abline(fm3)
anova(fm3, fm1) # lack of fit test
opar <- par(mfrow = c(2,2))
plot(fm3, main = "Continuous fit to data in Example 10.5")
par(opar)