The statistics table will help you understand more about the distribution of ratings in these data. While the default table is very wide, you can easily pivot it to column format.

step Double-click the table to activate it.

step From the Viewer menus choose:

Pivot
 Transpose Rows and Columns

  • 32 beta testers completed the task and submitted ratings.
  • At 9.94, the average rating is almost exactly at the center of the scale.
  • The standard deviation is most useful as an index of variability in normal distributions. However, the runs test does not make any assumptions about normality, and we know from the bar chart that the distribution of ratings is not normal.
  • As we observed in the bar chart, the actual ratings ranged from a low of 6 to a high of 14.
  • The quartiles tell us that about half of the sample rated the Web site in the range 8 to 12. The median (10) is almost identical to the mean. Although the distribution of ratings is bimodal and not normal, it is also fairly symmetric.