Figure 1
From: Reappraisal of the glycerol test in patients with suspected Menière’s disease
Correlation between mean threshold reduction (MTR) and aggregate threshold reduction (ATR). Both the MTR and the ATR can assume only a limited number of values. As a consequence, there are generally multiple occurrences for each combination of these measures so that a standard scatter plot would be problematic. The problem was solved by plotting a circle for each MTR-ATR combination and adjusting the radius so that the area of the circle is proportional to the number of occurrences. The two dotted lines (one horizontal, the other vertical) represent criteria that generally lead to consistent decisions as to the presence of a glycerol induced effect. The few exceptions are marked by filled circles: Blue indicates that the MTR is equal to or greater than the associated criterion value while the ATR falls short of the corresponding threshold. Red indicates that the situation is just the other way round.