State the degrees of freedom and explain how you calculated it by hand. (this is the data set needed for this question). participant sleep time reaction time 1 7.5 0.82 2 7 0.84 3 6 0.76 4 7 0.9 5 8.5 0.66 6 7.75 0.86 7 6.75 0.72 8 6.25 0.86 9 7.75 0.86 10 7.25 0.74 11 6.5 0.77 12 8.5 0.93 13 6.25 0.9 14 7.25 0.88 15 5.5 0.84 16 8.25 0.7 17 7.25 0.7 18 5.5 0.82 19 6 0.81 20 6.25 0.8