- Back in the Excel file, mouse over to select and copy columns B-C (not the newly created column D).
- Press the Clear button and then paste the 2 columns at once into the Paired Data box. Press Use Data.
You should see red and blue dots, with the two times for each individual connected, as well as the dotplot of the differences. Make sure the summary statistics information matches from what you calculated earlier (the mean and SD of the differences).
- Check the Randomize box.
- Make sure the Animate box is checked and then press the Randomize button.
For each pair, a coin will be flipped to see which time will go in the first column and which in the second column (you will see them swapped whenever a heads is flipped). Once the times have been (potentially) rearranged in each pair, the set of differences will again be graphed and the mean of those simulated differences will appear in the graph to the right.
Ask now if you are not clear on what the simulation is doing.
- Press Randomize again. Did you get the same mean difference the second time? What does the applet report for the mean of the two means? For the standard deviation?
- Uncheck the Animate box and press Randomize several more times. How do the connecting lines behave after each randomization? Do they tend to be mostly "to the right" (bottom to top) or "to the left" (bottom to top) or evenly split between the two directions?
- Now set to Randomize 1000 times. Press Randomize.
- Enter the observed difference for our study in the Count Samples box and then use the pull-down menu to specify Greater Than, Less Than, or Beyond (both tails) to match your alternative hypothesis.