Thanks Mordred. Actually I feel good knowing it is such a complicated problem...I thought I was asking a stupid question which everyone else knows the answer.
I read some of the text. Of course, there are many concepts and equation I do not understand. But I have the impression that different scientists have different ideas about how to treat the CMB data and what the major cosmological parameters are. For example,
(1) some people think the 6 parameters in the lambda CDM model can allow the fitting of data;
(2) others say the Friedman universe entirely depend on the 4 parameters: density of radiation, density of matter, density of dark energy and hubble's constant;
(3) some others say the anisotropy spectrum depends on the 4 fundamental parameters: curvature, density of baryonic matter, density of dark energy and density of matter.
(4) some others present some more parameters which I have not yet looked to see what they are.
......
I do not know if scientists today have a common agreement already. I am confused by how these parameters play in making the curve in the temperature power spectrum, or to say it in a bigger picture, in making up our universe.