Description
We use spectroscopic observations of a sample of 82 HII regions in 76 blue compact galaxies to determine the primordial helium abundance Yp and the slope dY/dZ from the Y-O/H linear regression. To improve the accuracy of the dY/dZ measurement, we have included new spectrophotometric observations of 33 HII regions that span a large metallicity range, with oxygen abundance 12+log(O/H) varying between 7.43 and 8.30 (Z_{sun}_/30<=Z<=Z_{sun}_/4). Most of the new galaxies were selected from the First Byurakan, the Hamburg/SAO, and the University of Michigan objective prism surveys.
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