# Significant digits/rounding

I have a bunch of criteria to evaluate for a product, and each is scored on a scale from 0 to 5. Each criterion has a weight associated with it.

If I find the weighted score of a criterion, it is

weighted score = score * weight

Does the significant digits apply here where I should only take one significant digit for my weighted score (since there is only one significant digit in my scoring scale (0-5))? Is it necessary?

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Your question is confusing to me and maybe it is me. Is score an integer value? If not, are you concerned that some information will be lost when you multiply that by the weight? Regards – Amzoti Apr 24 '13 at 1:29
I am confused with this question myself, so I'll try to explain as best as possible. The score is an integer value. I'm concerned that because I am using one significant digit in the score, my weighted score will have one significant digit as well and it will be so coarse that the weighted score will not be beneficial to my results. Am I applying significant digits in the wrong method here? – O_O Apr 24 '13 at 22:49

## 1 Answer

mean and standard deviation: round to one more decimal place than your original data. [...] This suggestion follows Sullivan, Michael, Fundamentals of Statistics 3/e (Pearson Prentice Hall, 2011) page 118.

Source

So, I suggest keeping one digit after the decimal dot when reporting the weighted average.

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