A computer scientist is studying the tendency for a computers running a certain operating system to run more slowly as the operating system ages. She measures the time (in seconds) for a certain application to load for nine computers one month after installation and for seven computers six months after installation. The results are as follows:

One month after install: 84.3 53.2 127.3 201.3 174.2 246.2 149.4 156.4 103.3 Six months after install: 207.4 233.1 215.9 235.1 225.6 244.4 245.3 Find a 95% confidence interval for the mean difference in time to load between the first month and the sixth.