Z-Scores and Pearson Correlation: If we have scores that are expressed as standardized scores -- Z-Scores with a mean of zero and a variance of one -- then the formula for the Pearson Correlation becomes particularly simple.
PNG Formats. .PNG files in logo design and when you should use them. PNG is an acronym for Portable Network Graphics. PNGs are bitmpapped (raster/pixel based) image formats that can be used instead of GIF images or JPGs. PNG logo images are superior to other pixel based formats as they employ a âlosslessâ data compression system.
ARCHIVED: What is the PNG graphics file format? Portable Network Graphics (PNG) was developed as a replacement for the GIF standard, partly because of legal entanglements resulting from GIF's use of the patented LZW compression scheme, and partly because of GIF's many limitations. PNG is superior to GIF in many ways, offering the following features: 1  Images that are the same size or slightly smaller than their GIF counterparts, while keeping lossless compression.  Support for indexed colors, gray-scale, and RGB (millions of colors)