Randomisation will be blocked to increase the likelihood of equal group sizes, using a standard permutated block algorithm in which block sizes will be randomly chosen from 2, 4 and 6 to protect concealment.
Each block's size will be randomly chosen from the set (4, 6, 8), and be unknown to the researchers involved in the study.
In this section, 500 blocks were randomly selected from blocks in 60 test images.
In this case, we set signal length N = 256, and there are 64 blocks with uneven block size and the k = 4 active blocks were randomly extracted from the 64 blocks.
On each block of five trials, one of each image type would be randomly selected, presented, and then excluded from selection on subsequent trials in that block.
District administrative blocks were randomly selected and from selected blocks, gram panchayats (local level of administration with elected council governing a collection of four to seven villages) were then randomly selected.
Blocks were randomly selected from districts and residential areas from blocks so that, finally, four residential areas in the urban district, three in the suburban district and two in the rural district were randomly selected (see Figures 1 and 2).
For a dataset with n observations, in the moving block bootstrap with block length l, the data is split into n − l + 1 blocks: block j consists of observations j to j + l − 1, j = 1,..., n − l + 1. [ n/b] blocks are randomly drawn from n − l + 1 blocks with replacement and are aligned in the order they are picked to form a bootstrap sample.
Four blocks (namely Joynagar II, Baruipur, Basanti and Gosaba) were randomly selected from 29 blocks of South 24 Parganas district.
The delay durations for the three trials within each block were randomly selected from permutations that allowed for a fixed total delay length of 9 sec per block (25% of blocks had three delays of 3 sec, in the remaining blocks one of the six possible permutations of 1.5, 3 and 4.5 sec was selected at random).
