Enter a z-score, choose a precision, and the script will return the approximated percentage. It's very simple. For reference, a z-score (or standardized score) tells you how far a number is from the average, in terms of standard deviations. Positive is above average, negative is below average. It helps compare scores and see how common or unusual a value is. I haven't yet managed to find a Scratch project that converts between z-scores and percentages.
Formula for z-score to percentage was adapted from Abramowitz & Stegun's "Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables," 1964. Formula for percentage to z-score was adapted from Moro "The Full Monte Carlo Approach to the Inverse Normal Distribution Function," 1995, based on Beasley & Springer, 1977. I used https://ztable.io/ to verify results the calculator was producing. Made in <25 minutes (I was bored and needed help with my homework) #mathisfun