xmp13.09 {Devore6} | R Documentation

## data from Example 13.9

### Description

The `xmp13.09` data frame has 8 rows and 2 columns of data on cure temperature and ultimate sheer strength of rubber compounds.

### Format

This data frame contains the following columns:

tempture
  cure temperature (degrees Fahrenheit).
strength
  ultimate sheer strength (psi)

### Examples

    data(xmp13.09)
    plot(strength ~ tempture, data = xmp13.09)
    fm1 <- lm(strength ~ tempture + I(tempture^2), data = xmp13.09)
    summary(fm1)
    xmp13.09$Tcentered <- scale(xmp13.09$tempture, scale = FALSE)
    fm2 <- lm(strength ~ Tcentered + I(Tcentered^2), data = xmp13.09)
    summary(fm2)
    ## another approach using orthogonal polynomials
    fm3 <- lm(strength ~ poly(tempture, 2), data = xmp13.09)
    summary(fm3)

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