Say we have a bunch of numbers like 9, 2, 5, 4, 12, 7, 8, 11. To calculate the standard deviation of those numbers: 1  1. 2  Work out the Mean (the simple average of the numbers). 3  2. Then for each number: subtract the Mean and square the result. 4  3. Then work out the mean of those squared differences.5  4. Take the square root of that and we are done!o calculate the standard deviation of those numbers: 1  1. 2  Work out the Mean (the simple average of the numbers). 3  2. Then for each number: subtract the Mean and square the result.
Best Answer: The .925 does mean sterling silver and the FB may be a Hallmark. You did not state what is on the medallion so I don't know where it was made. On some silver items the FB stands for Franz Bibus a Czech silversmith.
In the U.S., solid gold jewelry is marked with the purity and the hallmark (trademark) of the maker. So, for example, my wedding ring is marked 14K FG which means it is 14 karat gold, made by Frederick Goldman, Inc.The maker's hallmark can usually be found by searching the US Patent and Trademark Office's trademark database (but the search will probably be tedious).here is, however, an exception, and that is that GF is the standard abbreviation for gold filled which means it is a cheaper metal core coated with gold on the outside. In other words, it is not solid gold.