The following video clearly describes how to find the mean and the standard deviation of a set of data. You may watch more than once to get a clear idea of the use, after which it will become quite natural to you.

Mean, μ = Σx/n where n is the number of data; Standard Deviation, σ = Σ(x-μ)^{2}/n

The following video clearly describes how to find the mean and the standard deviation of a set of data in a table. You may watch more than once to be familiar with entering data in a table.

Mean, μ = Σfx/Σf where f is the number of data of each class; Standard Deviation, σ = Σf(x-μ)^{2}/Σf

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