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224 PART III: Experimental Methods3 To compensate for the three subjects lost, similar “participants” were dropped from the controlgroup (scores of 2, 1, and 1). The new mean for the control group was 6.06. This improved theinitial comparability of the two groups.4 The means for the four groups when one of the authors did this were: (1) 5.6 (2) 4.8 (3) 5.3, and(4) 6.3, indicating greater variability in the average memory ability score across the groups.The fewer the participants randomly assigned to conditions, the more difficult it is for randomassignment to create, on average, equivalent groups. Now, put away the cards and get back tostudying Chapter 6!Answer to Challenge Question 1A The first step is to assign a number from 1 to 4 to the respective conditions: 1 Very Fast;2 Fast; 3 Slow; and 4 Very Slow. Then, using the random numbers, select foursequences of the numbers from 1 to 4. In doing this you skip any numbers greater than 4 andany number that is a repetition of a number already selected in the sequence. For example, ifthe first number you select is a 1, you skip all repetitions of 1 until you have selected all thenumbers for the sequence of 1 to 4. Following this procedure and working across the rowsof random numbers from left to right, we obtained the following four sequences for the fourblocks of the randomized block schedule. The order of the conditions for each block is alsopresented. The block-randomized schedule specifies the order of testing the conditions forthe first 16 participants in the experiment.Block 1: 1-4-3-2 Very Fast, Very Slow, Slow, FastBlock 2: 4-2-3-1 Very Slow, Fast, Slow, Very FastBlock 3: 1-3-2-4 Very Fast, Slow, Fast, Very SlowBlock 4: 2-3-4-1 Fast, Slow, Very Slow, Very FastB The investigator is taking a reasonable step to avoid selective subject loss, but restrictingparticipants to those who pass a stringent reaction time test entails the risk of decreasedexternal validity of the obtained findings.C The rooms can be balanced by assigning entire blocks from the block-randomized scheduleto be tested in each room. Usually, the number of blocks assigned to each room is equal,but this is not essential. For effective balancing, however, several blocks should be tested ineach room.