A glasshouse experiment was conducted to examine how different doses of a growth regulator affect plant height under controlled conditions. Six increasing doses (Dose) were each applied to four replicate plants, with each plant grown in a separate pot. The pots were arranged in a completely randomized design on a bench grid comprising four rows (Row) and six columns (Column). After six weeks, the height of each plant (in cm; Height) was measured. This setup enables analysis of the effect of growth regulator dose on plant height, while accounting for any potential spatial variation across the grid layout.
Format
A data frame with 5 variables: Pot, Row, Column, Dose, Height.
- Pot
Factor. Unique identifier for each pot (experimental unit).
- Row
Factor. Row position of the pot in the grid layout on the bench.
- Column
Factor. Column position of the pot in the grid layout on the bench.
- Dose
Factor. Applied dose of the growth regulator.
- Height
Numeric. Plant height (in centimeters) measured six weeks after treatment.
Source
Welham, S. J., Gezan, S. A., Clark, S. J., and Mead, A. (2015) Statistical Methods in Biology: Design and analysis of experiments and regression
Examples
anova(lm(Height ~ Column + Dose, data = heights))
#> Analysis of Variance Table
#>
#> Response: Height
#> Df Sum Sq Mean Sq F value Pr(>F)
#> Column 5 618.85 123.771 33.485 5.526e-07 ***
#> Dose 5 348.05 69.610 18.833 1.523e-05 ***
#> Residuals 13 48.05 3.696
#> ---
#> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1