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The monthly salaries (in thousands of dollars) of a sample of 5 sales representatives are as follows.13, 10, 9, 7, 6Send data to calculatorFind the standard deviation of this sample of monthly salaries. Round your answer to two decimal places.(If necessary, consult a list of formulas.)

User Vascop
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1 Answer

20 votes
20 votes

First, let's calculate the mean of this sample.

The mean is given by the sum of all values divided by the number of values:


\begin{gathered} \bar{x}=(13+10+9+7+6)/(5)\\ \\ \bar{x}=(45)/(5)\\ \\ \bar{x}=9 \end{gathered}

Now, we can use the formula below for the sample standard deviation:


\begin{gathered} s=\sqrt{\frac{\sum_(i=1)^N(x_i-\bar{x})^2}{N-1}}\\ \\ s=\sqrt{((13-9)^2+(10-9)^2+(9-9)^2+(7-9)^2+(6-9)^2)/(5-1)}\\ \\ s=\sqrt{(16+1+0+4+9)/(4)}\\ \\ s=\sqrt{(30)/(4)}\\ \\ s=√(7.5)\\ \\ s=2.74 \end{gathered}

Therefore the sample standard deviation is 2.74, which represents a salary of $2740.

User Syed Umer Hasan
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