1. The average salary of senior high school teachers is ₱ 21,200. Assume a normal distribution with
standard deviation of ₱ 2,500. What is the probability that the mean for a sample of 36 teachers’
salaries is less than ₱20,000?



2. At a large manufacturing company, the mean age of workers is 37 years, and the standard deviation
is 6. Assume that the variable is normally distributed. If a random sample of 44 workers is selected,
find the probability that the mean age of the workers in the sample is between 36 and 40 years.