A<-c(264,260,258,241,262,255)
B<-c(208,220,216,200,213,206)
C<-c(220,213,219,225,230,228)
D<-c(217,226,215,227,220,222)

df<-data.frame(A=A,B=B,C=C,D=D) 
df
##     A   B   C   D
## 1 264 208 220 217
## 2 260 220 213 226
## 3 258 216 219 215
## 4 241 200 225 227
## 5 262 213 230 220
## 6 255 206 228 222
N=24
n=6
k=4
SCT=sum(df*df)-sum(df)**2/N
SCT
## [1] 8150.958
st=sapply(df,sum)
n<-sapply(df,length)
SCTrat=sum(st*st/n)-sum(df)**2/N
SCTrat
## [1] 7227.792
SCE=SCT-SCTrat
SCE
## [1] 923.1667
CMTrat=SCTrat/(k-1)
CMTrat
## [1] 2409.264
CME=SCE/(N-k)
CME
## [1] 46.15833
Fo=CMTrat/CME
Fo
## [1] 52.19564
qf(0.95,k-1,N-k)
## [1] 3.098391
1-pf(Fo,k-1,N-k)
## [1] 1.217115e-09
df<-stack(df)
df
##    values ind
## 1     264   A
## 2     260   A
## 3     258   A
## 4     241   A
## 5     262   A
## 6     255   A
## 7     208   B
## 8     220   B
## 9     216   B
## 10    200   B
## 11    213   B
## 12    206   B
## 13    220   C
## 14    213   C
## 15    219   C
## 16    225   C
## 17    230   C
## 18    228   C
## 19    217   D
## 20    226   D
## 21    215   D
## 22    227   D
## 23    220   D
## 24    222   D
names(df)=c("Y","Trat")
str(df)
## 'data.frame':    24 obs. of  2 variables:
##  $ Y   : num  264 260 258 241 262 255 208 220 216 200 ...
##  $ Trat: Factor w/ 4 levels "A","B","C","D": 1 1 1 1 1 1 2 2 2 2 ...
modelo<-aov(Y~Trat,data=df)
summary(modelo)
##             Df Sum Sq Mean Sq F value   Pr(>F)    
## Trat         3   7228  2409.3    52.2 1.22e-09 ***
## Residuals   20    923    46.2                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1