Dr. Susan Benner is an industrial psychologist. She is currently studying stress among executives of Internet companies. She has developed a questionnaire that she believes measures stress. A score above 80 indicates stress at a dangerous level. A random sample of 15 executives revealed the following stress level scores.
94 78 83 90 78 99 97 90 97 90
93 94 100 75 84
a. Find the mean stress level for this sample. What is the point estimate of the population mean ?
b. Construct a 95 percent confidence level for the population mean.
c. Is it reasonable to conclude that Internet executives have a mean stress level in the dangerous level, according to Dr. Benner's test ?