A new operating system is installed at every workstation at a large company. The claim of the operating system manufacturers is that the time to shut down and turn on the machine will be much faster. To test it an employee selects 35 machines and tests the combined shut down and restart time of each machine before and after the new operating system has been installed.The mean of the differences (Before-After) is 24.9 seconds, with a standard deviation of 25 seconds.
What is the standard error of the mean difference? ___
How many degrees of freedom does the T statistif have? ___
What is the 95% Confidence interval for the mean difference? __ , ____