1. A university wants to determine the proportion of students who use a cash card to pay at the university food service. Out of 100 students surveyed, 75 students use a cash card. What is the 98% confidence interval for the population proportion?
2. A random sample of 85 supervisors revealed that they worked an average of 6.5 years before being promoted. The population standard deviation was 1.7 years. Using a 99% confidence, what is the confidence interval for the population mean?