A computer system administrator notices that computers running aparticular operating system seem to freeze up more often as theinstallation of the operating system ages. She measures the time(in minutes) before freeze-up for seven computers one month afterinstallation, and for nine computers seven months afterinstallation. The results are as follows: One month after install:207.4 233.1 215.9 235.1 225.6 244.4 245.3 Seven months afterinstall: 84.3 53.2 127.3 201.3 174.2 246.2 149.4 156.4 102.3 Let ?Xrepresent the population mean for the first month and let ?Yrepresent the population mean for the seventh month. Find a 95%confidence interval for the difference ?X??Y . Round down thedegrees of freedom to the nearest integer and round the answers tothree decimal places.
