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.
When to Use PNG. Use PNG when you need smaller file sizes with no loss in quality. PNG files are usually smaller than TIFF images. PNG also supports alpha transparency (soft edges) and was developed to be a Web graphics replacement for GIF. Note that if you want to retain full transparency, you will need to save your PNG file as PNG-24 and not PNG-8.