Comparison between the pressure and 1D SZ fluctuations probability distributions for model 1 (gaussian) and model 2 (lognormal), and MACS J0717.5+3745 data. Left: probability density function of the pressure fluctuations $1+\delta P/\overline{P}$ for model 1 (gaussian fluctuations) and model 2 (lognormal fluctuations). Middle: probability density function of the SZ fluctuations $1+\frac{\delta y}{\overline{y}}$ for model 1 and model 2, without noise. Right: probability density function of the SZ fluctuations $1+\frac{\delta y}{\overline{y}}$ for model 1 and model 2, including noise, and comparison with MACS J0717.5+3745 NIKA data. The data and model were smoothed with a 10 arcsec FWHM gaussian kernel to reduce the noise. The mean distributions and error bars were obtained from the mean and standard deviations, respectively, of 100 Monte Carlo realizations.