## 3 Results  
### Descriptive Statistics  
Figure 1 shows histogram distributions of the different categories based on the status of the participants. Males tend to smoke more than females, while the patterns regarding alcohol consumption are similar for both genders. Additionally, females tend to consume more coffee than males. Moreover, both females and males frequently confirmed that they were not voice users. Figure 2 presents distributions of various acoustic parameters in the form of box plots, which provide better visualization before and after treatment for females and males. As shown in Figure 2a, for females, F0 showed a distribution ranging from 80 Hz to 316 Hz before treatment (Pre-tx), with a median of 194 Hz, and a distribution ranging from 131 Hz to 242 Hz after treatment (Post-tx), with a median of 204 Hz. For males, F0 showed a distribution ranging from 85 Hz to 230 Hz before treatment, with a median of 144 Hz, and a distribution ranging from 87 Hz to 235 Hz after treatment, with a median of 147 Hz. As shown in Table 2, the pre- and post-treatment F0 values for both genders were not  
Figure 1: Histogram distributions of different categories based on the status of the participants. significantly different and exhibited a typical positive linear correlation. Based on the results, as F0 exhibits differences based on gender, it is essential to examine the patterns according to gender when analyzing variables related to F0. Jitter reflects the consistency of the oscillation cycle and the variation in the F0 mean, and it is associated with the level of roughness. As shown in Figure 2b, jitter values showed significant differences both before and after treatment for both female and male voices (\(p<0.001\)), although jitter extracted from male voices showed a weak correlation. For females, jitter showed a distribution ranging from 0.2% to 7.854% before treatment (Pre-tx), with a median of 2.166%, and a distribution ranging from 0.296% to 2.920% after treatment (Post-tx), with a median of 1.144%. For males, it showed a distribution ranging from 0.318% to 4.340% before treatment, with a median of 2.173%, and a distribution ranging from 0.304% to 2.444% after treatment, with a median of 0.628%. The diagram presented in Figure 2c illustrates the perturbation of glottic vibration, signifying the amplitude of the sound wave. This perturbation is linked to alterations in the level of voice breathiness and variations in intensity. Similar results were observed for shimmer (\(p<0.001\) and \(p=0.013\)) as seen for jitter, although shimmer showed weak correlations for both females and males. For females, shimmer showed a distribution ranging from 1.075% to 16.681% before treatment (Pre-tx), with a median of 4.15%, and a distribution ranging from 0.237 to 7.394% after treatment (Post-tx), with a median of 2.792%. For males, it showed a distribution ranging from 1.861% to 28.831% before treatment, with a median of 4.10%, and a distribution ranging from 1.662% to 11.995% after treatment, with a median of 3.107%. In Figure 2d, NHR represents the quantity of noise present within the harmonics of the waveform. A higher NHR value indicates a lower overall sound quality level. SFF and MPT in Figure 2e,f refer to the fundamental frequency at which a person speaks and the maximum duration of sustained phonation or vocalization that a person can produce in a single breath, respectively. The results show that, as shown in Figure 2d-f and Table 2, female voices exhibited significant differences in NHR, while male voices showed significant differences in MPT. Both genders exhibited a strong positive correlation of 0.7 or higher in terms of SFF and MPT.