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Find the standard deviation for the given sample data. Round your answer to one more decimal place than the original data.17) 10.8, 15.3 , 48.6, 45.1, 21.3, 19.9

User Csknk
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1 Answer

24 votes
24 votes

The standard deviation for a sample is given by:


s=\sqrt[]{\frac{\sum^n_(i\mathop=1)(x_i-\bar{x})}{n-1}}

where n is the sample size, xi are the values of the data and x bar is the mean of the data.

Let's find the mean first:


\begin{gathered} \bar{x}=(\sum ^n_(i\mathop=1)x_i)/(n) \\ \bar{x}=(10.8+15.3+48.6+45.1+21.3+19.9)/(6) \\ \bar{x}=(161)/(6) \\ \bar{x}=26.83 \end{gathered}

Now that we have the mean we can calculate the standard deviation:


\begin{gathered} s=\sqrt[]{\frac{\sum^n_{i\mathop{=}1}(x_i-\bar{x})}{n-1}} \\ =\sqrt[]{((10.8-26.83)^2+(15.3-26.83)^2+(48.6-26.83)^2+(45.1-26.83)^2+(21.3-26.83)^2+(19.9-26.83)^2)/(6-1)} \\ =\sqrt[]{(1276.2334)/(5)} \\ =15.98 \end{gathered}

Therefore, the standard deviation of the data is 15.98

User Dan Gravell
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