Figure 5: Box-whisker plot of the three parameters, derived from the sound frequency spectra of each volunteer (reproduced from Neurourol. Urodyn., with kind permission of John Wiley and Sons, Inc.). The box represents the median value and the 25th and 75th percentile and the whiskers represent the highest and lowest value. Volunteers that were significantly different from three or more other volunteers (Dunnís test, P< 0.05) are marked with an asterisk. The number 1 identifies a volunteer that was significantly at the top end of the weighted average frequency and the standard deviation scale and at the bottom end of the skewness scale.