 This is a paired samples problem. We're given eight samples with the time of last beginning and at the end and we need to find the differences. As part of the paired samples t-test though you're often asked to find d bar which is the mean of the differences and s of d which is standard deviation of the differences. And StatCrunch doesn't give you both of those neatly built into the hypothesis calculators. But here's how you can get those. Let's go ahead and run the hypothesis test. This is paired sample and we're going to select the beginning time, the end time, and here's the key part. Click on save the differences and then we're going to run the test. Put this out of the way. There's our differences d, little d. And all we need to do then is just go to summary stats, columns, pick differences and then select the mean, hold down the control key, standard deviation, and click compute and those are the answers. That is d bar which is the mean of the differences and standard deviation of the differences which is s of d.