performance. The second two night, the researcher asked these same participants to sleep for only four h perform worse on the cognitive task after sleep deprivation (a = .05). This data is below: 8 hours sleep 4 hours sleep 12 10 10 9 15 14 12 8 8 7 8 S = 2.53 s= 2.5 D = 10 D2 = 24 What is the mean of the difference scores (D)? ort Moving to another question will save this response. ce