  Much attention has been given to the problem of estimating cosmological
parameters from the $C_l$ measured by future experiments. Many of the
approaches which are being used either invoke poorly controlled approximations
or are computationally expensive. We derive exact results as well as fast and
highly accurate approximations for mapping a theoretical model onto the
observed power spectrum coefficients and computing their statistical
properties. These results obtain from an analytic framework which applies for
any azimuthally symmetric sky coverage regardless of the fraction of the sky
observed by the experiment.
