The Quantiles report lists selected percentiles for each level of the X factor variable. The median is the 50th percentile, and the 25th and 75th percentiles are called the quartiles.
The Quantiles option adds the following elements to the plot:
• the grand mean representing the overall mean of the Y variable
• outlier box plots summarizing the distribution of points at each factor level
Figure 6.6 Outlier Box Plot and Grand Mean
Note: To hide these elements, click the red triangle next to Oneway Analysis and select Display Options > Box Plots or Grand Mean.