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.
Image Guidelines. 1  Appear on page at 820 x 312 pixels. 2  Minimum size of 399 x 150 pixels. 3  Displays at 820 x 312 pixels on desktop and 640 x 360 pixels on smartphones. 4  Doesnât display on feature phones. 5  For best results, upload an sRGB JPG file less than 100 KB. 6  Images with a logo or text may be best as a PNG file.