A Group of Statistics Students Decided to Conduct a Survey

Multiple Choice

A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students study per week. Based on a simple random sample, they surveyed 144 students. The statistics showed that students studied an average of 20 hours per week with a standard deviation of 10 hours. What is the probability of finding a sample mean less than 18 hours?

A) 0.4820
B) 0.4918
C) 0.0082
D) 0.0181