Disclaimer: Statistical math person I am not...
I'm a programmer that has been tasked with finding the percentile a child will fall in depending on their weight and age according to the CDC.
The CDC site with the data is: http://www.cdc.gov/growthcharts/percentile_data_files.htm
I am using the Weight-for-age data from the CDC and I beleive I can obtain the correct z-score for a child given their weight for age. Now that I have a z-score...what do I do? How can I turn that Z-Score into a percentile? From what I've researched it sounds like I need a standard normal table find the percentile, but can I use any standard normal table I find? How exactly do I get the corresponding percentile for a given Z-Score? I am even on the right track?
EDIT: I would like to get childs specific percentile for their weight if possible. The data tables provided by the cdc give percentages in increments (ie: 3, 5, 10), but I would like to know if a child falls into the 2nd percentile. I just don't know if getting an exact percentile is possible.