Interval Estimation 1) Installation of a certain hardware takes a random amount of time with a standard deviation of 5 minutes. A computer technician installs this hardware on 64 different computers with the average installation time of 42 minutes. Compute a 95% confidence interval for the mean installation time. 2) Professors are concerned about the impact of PhD candidates working part-time while they are enrolled in classes. They would like to know if students are overworking and therefore spending less time on coursework and research. Professors decided to find out, on average how many hours the students are working per week. From previous experiences, they know that the standard deviation of this variable is 5 hours. They surveyed 200 students. 3) A student is conducting a survey using data on study hours collected from a random sample of 100 students at NSU. She finds 95% confidence interval for the mean study hours to be (12.5, 15). She states that she is 95% sure that all the students study between 12.5 to 15 hours. Do you agree with this statement? Explain your answer.