library(GAD)
## Loading required package: matrixStats
## Warning: package 'matrixStats' was built under R version 4.2.2
## Loading required package: R.methodsS3
## R.methodsS3 v1.8.2 (2022-06-13 22:00:14 UTC) successfully loaded. See ?R.methodsS3 for help.
proc <- c(rep(1,4),rep(2,4),rep(3,4),rep(1,4),rep(2,4),rep(3,4),rep(1,4),rep(2,4),rep(3,4))
batch <- c(rep(seq(1,4),9))
obs <- c(25,19,15,15,29,23,28,35,24,35,38,25,30,28,17,16,27,24,21,27,25,21,34,29,26,20,14,13,24,21,27,25,20,24,30,33)
proc <- as.fixed(proc)
batch <- as.random(batch)
dat1 <- data.frame(proc,batch,obs)
dat1
##    proc batch obs
## 1     1     1  25
## 2     1     2  19
## 3     1     3  15
## 4     1     4  15
## 5     2     1  29
## 6     2     2  23
## 7     2     3  28
## 8     2     4  35
## 9     3     1  24
## 10    3     2  35
## 11    3     3  38
## 12    3     4  25
## 13    1     1  30
## 14    1     2  28
## 15    1     3  17
## 16    1     4  16
## 17    2     1  27
## 18    2     2  24
## 19    2     3  21
## 20    2     4  27
## 21    3     1  25
## 22    3     2  21
## 23    3     3  34
## 24    3     4  29
## 25    1     1  26
## 26    1     2  20
## 27    1     3  14
## 28    1     4  13
## 29    2     1  24
## 30    2     2  21
## 31    2     3  27
## 32    2     4  25
## 33    3     1  20
## 34    3     2  24
## 35    3     3  30
## 36    3     4  33

a)

\(y_{ijk}=\alpha_i+\beta_{j(i)}+\epsilon_{ijk}\)

b)

\(H_{0A}: \alpha_i=0,H_{1A}: \alpha_i\ne0\)

\(H_{0B}:\sigma^2_{j(i)}=0,H_{1B}:\sigma^2_{j(i)}\ne0\)

c)

model <- lm(obs~proc+batch%in%proc)
gad(model)
## Analysis of Variance Table
## 
## Response: obs
##            Df Sum Sq Mean Sq F value   Pr(>F)   
## proc        2 446.06 223.028  3.5365 0.073563 . 
## proc:batch  9 567.58  63.065  4.1965 0.002349 **
## Residual   24 360.67  15.028                    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

From this analysis we can see that only the nested factor (batch) is significant (\(\alpha=0.05\)) and the process (factor A) does not significantly affect the burning rate of propellant (observeation).