Balanced Incomplete Block Designs Data X(i,j) J(i,j)=0,1 where Observation X(i,j) is present if J(i,j)=1, otherwise missing 1 le i le nn Subjects or Blocks 1 le j le kk Treatments or Treatment Groups ss observations in each block (Sum(j=1,k) J(i,j)=ss, all i) pp observations for each treatment (Sum(i=1,n) J(i,j)=pp, all j) lam observations common between every pair of treatments Example: Percent conversion of Methyl Glucoside to Monovinyl Isomers in presence of acetylene and a strong base under high pressure See Table 7.14 (p316) in text Data: Run 250psi 325psi 400psi 475psi 550psi 1. 16 18 32 2. 19 46 45 3. 26 39 61 4. 21 35 55 5. 19 47 48 6. 20 33 31 7. 13 13 34 8. 21 30 52 9. 24 10 50 10. 24 31 37 k=5 treatments and n=10 blocks (runs) ss=3 observations in each block pp=6 observations in each treatment group lam=3 observations in each pair of treatment groups Total number of observations: 10x3 = 5*6 = 30 These two numbers should be the same: pp*(ss-1)=12 lam*(kk-1)=12 Within-block ranks at observed values: Run 250psi 325psi 400psi 475psi 550psi 1. 1.0 2.0 3.0 2. 1.0 3.0 2.0 3. 1.0 2.0 3.0 4. 1.0 2.0 3.0 5. 1.0 2.0 3.0 6. 1.0 3.0 2.0 7. 1.5 1.5 3.0 8. 1.0 2.0 3.0 9. 2.0 1.0 3.0 10. 1.0 2.0 3.0 Observed treatment-group rank sums: 7.5 7.5 13.0 15.0 17.0 Observed rank-sum score for permutations: Lscore=795.5 Large-sample approximation: Durbin etal test: D=15.1 P=0.00450 (df=4) Carrying out Nsims=100000 Friedman-like permutations: Initializing the random-number generator at 12345678 Lscore = Sum of Squares over Treatment Groups of Treatment-Group Rank Sums: Observed Lscore=795.5 Number of simulations with values >= Lscore and total number: 22 100000 95% CI for true P-value bracketing estimate of true pvalue: (Since Lscore >= 0, P-values are inherently two-sided.) (0.00013 0.00022 0.00031)