function () 
{
    life = Battery$life
    temperature = as.factor(Battery$temp)
    MaterialType = as.factor(Battery$type)
    out.lm = lm(life ~ temperature + MaterialType)
    out.lm.full = lm(life ~ temperature * MaterialType)
    plot(out.lm$fitted.values, out.lm$residuals)
    readline()
    qqnorm(out.lm$residuals)
    qqline(out.lm$residuals)
    readline()
    plot(out.lm.full$fitted.values, out.lm.full$residuals)
    readline()
    qqnorm(out.lm.full$residuals)
    qqline(out.lm.full$residuals)
    readline()
    par(mfcol = c(2, 1))
    interaction.plot(temperature, MaterialType, life)
    interaction.plot(MaterialType, temperature, life)
    list(anova(out.lm), anova(out.lm.full))
}