We compare the pdf and its low-order moments ( variance and skewness ) of the smoothed PSCz galaxy density field and of the corresponding simulated PSCz look-alikes , generated from N-body simulations of 6 different DM models ; four structure normalized with \Gamma = 0.25 and \sigma _ { 8 } = 0.55 \Omega _ { \circ } ^ { -0.6 } , one COBE normalized and the old SCDM .
The galaxy distributions are smoothed with a Gaussian window at three different smoothing scales R _ { sm } = 5 , 10 and 15 h ^ { -1 } { Mpc } .
We find that the simulation PSCz look-alike pdf ’ s are sensitive only on the normalization of the power spectrum , probably due to shape similarity of the simulated galaxy power spectrum on the relevant scales .
We find that the only models that are consistent , at a high significance level , with the observed PSCz pdf are models with a relatively low power spectrum normalization ( \sigma _ { 8 } = 0.83 ) .
From the phenomenologically derived \sigma _ { 8 } - moments relation , fitted from the simulation data , we find that the PSCz moments suggest \sigma _ { 8 } \simeq 0.7 .

Keywords : cosmology : theory - galaxies : general - large-scale structure of universe - Infrared : galaxies