• Toggle to the Excel file and use your mouse to select both columns of data in the Excel file, also being sure to include the (one-word) column titles (and all rows of data). Copy these columns to the clipboard(e.g., ctrl-C).
• In the applet, press Clear and then in the Sample data window, paste the data (e.g., ctrl-V). Press Use Data. You should see a copy of the stacked dotplots you previously created (confirm that the numerical summary information matches).
• Check the Show Shuffle Options box to the right.
• Select the Plot radio button.
• Press the Shuffle Responses button once and watch the dots.
• Once the scores have been redistributed to the groups, the groups means have changed and so has the difference we compute between the two groups (JFK - JFKC) has changed. This new hypothetical difference in group means is added to the dotplot to the right.
• Press the Shuffle Responses button again. Do you get the same difference in group means this time?
• Press the Shuffle Responses button a few more times and watch how the redistributed groups vary with each random assignment. Are you beginning to see a pattern in the dotplot of the shuffled differences?
  
  

  This is a good time to ask for help if you don't understand what is going on here. (Hint: What are the observational units and variable in this dotplot?)



• Change the Number of repetitions to 1000 and press the Shuffle Responses button.
• To approximate the p-value, we want to know how many of these simulated differences in group means are at least as large (in the direction conjectured by the researchers) as the one observed. Recall the value of the difference in group means observed in our study (see (b)), and type that in the box next to Count samples box. Then press Count. The histogram should shade the values at least as extreme and report the empirical (estimated) p-value.