How long do RN's work in the nursing field? The answer might vary depending on the age of the nurse when he or she obtained the RN degree. A random sample of 80 retired nurses who received their RN's before age thirty was surveyed. The mean length of time they worked as an RN was 9.7 years with standard deviation 2.8 years. An independent random sample of 70 retired nurses who received their RN degrees at age thirty or later indicated that their mean length of service in the profession was 10.2 years with standard deviation 2.4 years. Test to see if the nurses who get their RN degrees later in life stay in the profession longer. Use a 1% significance level.