# Question -7

Discrete Mathematics Level 3

If $$\displaystyle \sum_{i=1}^{18} (x_i-8)=9$$ and $$\displaystyle \sum_{j=1}^{18} (x_j-8)^2=45$$, then the standard deviation of $$x_1,x_2,x_3,...,x_{18}$$ is:

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