New hospital employs 200 people on the nursing staff. sixty are nurse’s aides, seventy are practical nurses and seventy are registered nurses. nurse’s aides receive $ 15 an hour, practical nurses $ 25 an hour and registered nurses $ 30 an hour. what is the (weighted mean) hourly average wage of the nursing staff?

In a survey of 1015 adults, a polling agency asked, "when you retire, do you think you will have enough money to live comfortably or not. of the 1015 surveyed, 534 stated that they were worried about having enough money to live comfortably in retirement. construct a 90% confidence interval for the proportion of adults who are worried about having enough money to live comfortably in retirement.