for a sample with a standard deviation of s=10, a score of x=65 corresponds to z=1.50. what is the sample mean? Solution change the values and take help: mean: = 65 and standard deviation: = 15 Approximately 68.3% of the students who wrote this exam had marks between 50 and 80. Approximately 95.4% of the students who wrote this exam had marks between 35 and 95..