mead.germination {agridat} | R Documentation

## Seed germination with different temperatures/concentrations

### Description

Seed germination with different temperatures/concentrations

### Format

A data frame with 64 observations on the following 5 variables.

`temp`

  temperature regimen

`rep`

  replication factor (not blocking)

`conc`

  chemical concentration

`germ`

  number of seeds germinating

`seeds`

  number of seeds tested = 50

### Details

The rep factor is NOT a blocking factor.

### Source

Roger Mead, Robert N Curnow, Anne M Hasted. 2002. Statistical Methods in Agriculture and Experimental Biology, 3rd ed. Chapman and Hall. Page 350-351.

Used with permission of Roger Mead, Robert Curnow, and Anne Hasted.

### References

Schabenberger, O. and Pierce, F.J., 2002. Contemporary statistical models for the plant and soil sciences, CRC.

### Examples

    data(mead.germination)
    dat <- mead.germination
    dat <- transform(dat, concf=factor(conc))
    require(lattice)
    xyplot(germ~log(conc+.01)|temp, dat, layout=c(4,1),
           main="mead.germination", ylab="number of seeds germinating")

    m1 <- glm(cbind(germ, seeds-germ) ~ 1, dat, family=binomial)
    m2 <- glm(cbind(germ, seeds-germ) ~ temp, dat, family=binomial)
    m3 <- glm(cbind(germ, seeds-germ) ~ concf, dat, family=binomial)
    m4 <- glm(cbind(germ, seeds-germ) ~ temp + concf, dat, family=binomial)
    m5 <- glm(cbind(germ, seeds-germ) ~ temp * concf, dat, family=binomial)
    anova(m1,m2,m3,m4,m5)
    ##   Resid. Df Resid. Dev Df Deviance
    ## 1        63    1193.80
    ## 2        60     430.11  3   763.69
    ## 3        60     980.10  0  -549.98
    ## 4        57     148.11  3   831.99
    ## 5        48      55.64  9    92.46

    # Show logit and fitted values.  T2 has highest germination
    subset(cbind(dat, predict(m5), fitted(m5)), rep=="R1")

[Package agridat version 1.16 Index]