Z=(5- 7)/1.7 = – 1.18 Look up percentile rank for z= 1.18 in table. Value given is about 12 What percent slept more than 10 hours? Standardized score = (10- 7)/1.7 = 1.76 Look up z=1.76. Closest z in table is 1.75 This is 96th percentile. What percent slept between 5 and 10 hours? Answer = 96% – 12% = 84% What value of sleep is the 60 percentile? Look for 60 under “Percentile” in table. Corresponding z is z = 0.25. What value of sleep has z = 0.25?