I have calculated the MEDIAN_CV_COVERAGE, however, what the meaning of this measurement? I have checked the related discuss at seqanswers  and asked the question there. In brief, if the MEDIAN_CV_COVERAGE as the defined on wiki, the calculated value should be larger than the output of picard. In my data sets, this value just range between 0.2 and 1.7. To my understand, this value will definitely larger than 0 for normal samples. Because the coverage for high expressed genes should be very high and the variation for the top 1000 highly expressed genes will be large. Am I right?