Example 2.1 from Experimental Design and Analysis for Tree Improvement

Exam2.1 is used to compare two seed lots by using single factor ANOVA.

References

1. E.R. Williams, C.E. Harwood and A.C. Matheson (2023). Experimental Design and Analysis for Tree Improvement. CSIRO Publishing (https://www.publish.csiro.au/book/3145/).

See also

DataExam2.1

Author

1. Muhammad Yaseen (myaseen208@gmail.com)

2. Sami Ullah (samiullahuos@gmail.com)

Examples

library(car)
#> Loading required package: carData
library(dae)
#> Loading required package: ggplot2
library(dplyr)
#> 
#> Attaching package: ‘dplyr’
#> The following object is masked from ‘package:car’:
#> 
#>     recode
#> The following objects are masked from ‘package:stats’:
#> 
#>     filter, lag
#> The following objects are masked from ‘package:base’:
#> 
#>     intersect, setdiff, setequal, union
library(emmeans)
#> Welcome to emmeans.
#> Caution: You lose important information if you filter this package's results.
#> See '? untidy'
library(ggplot2)
library(lmerTest)
#> Loading required package: lme4
#> Loading required package: Matrix
#> 
#> Attaching package: ‘lmerTest’
#> The following object is masked from ‘package:lme4’:
#> 
#>     lmer
#> The following object is masked from ‘package:stats’:
#> 
#>     step
library(magrittr)
library(predictmeans)
#> Loading required package: glmmTMB
#> Loading required package: nlme
#> 
#> Attaching package: ‘nlme’
#> The following object is masked from ‘package:lme4’:
#> 
#>     lmList
#> The following object is masked from ‘package:dplyr’:
#> 
#>     collapse

data(DataExam2.1)
# Pg. 22
fmtab2.3  <- lm(formula = dbh ~ seedlot, data = DataExam2.1)
# Pg. 23
anova(fmtab2.3)
#> Analysis of Variance Table
#> 
#> Response: dbh
#>           Df Sum Sq Mean Sq F value  Pr(>F)  
#> seedlot    1  14.27 14.2695  3.2531 0.09284 .
#> Residuals 14  61.41  4.3864                  
#> ---
#> Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

# Pg. 23
emmeans(object = fmtab2.3, specs = ~ seedlot)
#>  seedlot emmean   SE df lower.CL upper.CL
#>  SO        30.6 0.74 14     29.0     32.2
#>  P         28.7 0.74 14     27.1     30.3
#> 
#> Confidence level used: 0.95 
emmip(object = fmtab2.3, formula = ~ seedlot) +
  theme_classic()