This study will use the block randomization method to generate a sequence of random numbers. In this method, 15 blocks of size 4 and 7 blocks of size two will be randomly selected from the combination of letters A and B with the table of random numbers.
The list of blocks with size two are 1:AB, 2:BA and the list of blocks with size four are 1:AABB, 2:ABBA, 3:BBAA, 4:BAAB, 5:BABA, 6:ABAB
To select blocks of size 2, 7 numbers randomly from the table of random numbers are selected; if this number is from 0 to 4, the first block, and if the number is from 5 to 9, the second block will be selected.
To select blocks of size 4, randomly 15 numbers between 1 to 6 will be selected from the table of random numbers; then, if this number is one, the first block of size four, and if the selected number is 2, the second block of size four and ..., will form our random sequence.
After determining the random sequence, each person's type of treatment is placed in sealed envelopes, and referring patients, if they meet the criteria for entering the study, will receive their type of treatment based on the sequence obtained.