xmp12.02 {Devore6} | R Documentation

## data from Example 12.2

### Description

The `xmp12.02` data frame has 19 rows and 2 columns.

### Format

This data frame contains the following columns:

soil.pH
  pH of the soil at the test site.
dieback
  mean crown dieback at the test site (%).

### Details

These data are from an observational study of the mean crown dieback, a measure of the growth retardation in sugar maples, and the soil pH.

### Source

Devore, J. L. (2003) Probability and Statistics for Engineering and the Sciences (6th ed), Duxbury

(1995) ``Relationships among crown condition, growth, and stand nutrition in seven northern Vermont sugarbushes'', Canadian Journal of Forest Research, 386–397

### Examples

    data(xmp12.02)
    plot(dieback ~ soil.pH, data = xmp12.02,
         xlab = "soil pH", ylab = "mean crown dieback (%)",
         main = "Data from Example 12.2, page 491")
    fm1 <- lm(dieback ~ soil.pH, data = xmp12.02)
    abline(fm1)
    summary(fm1)
    opar <- par(mfrow = c(2,2))
    plot(fm1)
    par(opar)

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