# mead.turnip: Density/spacing experiment for turnips in 3 blocks. In agridat: Agricultural Datasets

## Description

Density/spacing experiment for turnips in 3 blocks.

## Usage

 `1` ```data("mead.turnip") ```

## Format

A data frame with 60 observations on the following 4 variables.

`yield`

log yield (pounds/plot)

`block`

block

`spacing`

row spacing, inches

`density`

density of seeds, pounds/acre

## Details

An experiment with turnips, 3 blocks, 20 treatments in a factorial arrangement of 5 seeding rates (density) and 4 widths (spacing).

## Source

Roger Mead. (1988). The Design of Experiments: Statistical Principles for Practical Applications. Example 12.3. Page 323.

## References

H. P. Piepho, R. N. Edmondson. (2018). A tutorial on the statistical analysis of factorial experiments with qualitative and quantitative treatment factor levels. Jour Agronomy and Crop Science, 8, 1-27. https://doi.org/10.1111/jac.12267

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16``` ```data(mead.turnip) dat <- mead.turnip dat\$ratef <- factor(dat\$density) dat\$widthf <- factor(dat\$spacing) m1 <- aov(yield ~ block + ratef + widthf + ratef:widthf, data=dat) anova(m1) # table 12.10 in Mead # Similar to Piepho fig 10 if(require(lattice)) { xyplot(yield ~ log(spacing)|ratef, data=dat, auto.key=list(columns=5), main="mead.turnip - log(yield) for each density", group=ratef) } ```

### Example output ```Analysis of Variance Table

Response: yield
Df  Sum Sq Mean Sq  F value    Pr(>F)
block         2  3.4168  1.7084  43.6173 1.443e-10 ***
ratef         4 25.6476  6.4119 163.7023 < 2.2e-16 ***
widthf        3  0.9167  0.3056   7.8011  0.000353 ***
ratef:widthf 12  0.9976  0.0831   2.1224  0.038910 *
Residuals    38  1.4884  0.0392
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1