Value of reduced temperature equal to that of reduced pressure?

[Outrageous]

I only know that a pure gas at same reduced temperature and reduced pressure will have same compressibility factor.
But I wondered is this correct? value of reduced temperature equal to that of reduced pressure?
from
http://www.answers.com/topic/law-of-corresponding-states


One more question,from wiki "In order to obtain a generalized graph that can be used for many different gases, the reduced pressure and temperature, and , are used to normalize the compressibility factor data. " What is the experiment? and How to draw the generalized graph ?
from
http://en.wikipedia.org/wiki/Compressibility_factor

THANK YOU

 

[Future Bruno]

The Law of Corresponding States states that all pure gases at the same reduced temperature and pressure will have the same compressibility factor. The reduced temperature is defined as the absolute temperature divided by the critical temperature of the gas, and the reduced pressure is defined as the absolute pressure divided by the critical pressure of the gas. To draw a generalized graph for many different gases, the compressibility factor data from multiple gases is normalized using the reduced temperature and pressure values. The normalized data is then plotted on a graph and the resulting graph can be used to estimate the compressibility factor of any gas at the given reduced temperature and pressure.