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the random sample of 10 airline carry on luggage bags gave the following weights 38,45,27,42,17,36,10,21,33,36 find the variance and the standard deviation

User TotsieMae
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1 Answer

6 votes

We need to use the variance and standard deviation for a sample:

The equation for a variance is:


s^2=(\Sigma(x-x^-)^2)/(n-1)

Where x⁻ is the mean of x and n is the total number of values.

First, let us find the mean:


Mean=(38+45+27+42+17+36+10+21+33+36)/(10)

Then :


mean=30.5

Now, we can find the variance:


s^2=(\Sigma x-30.5)/(10-1)=((38-30.5)+(45-30.5)+(27-30.5)+(42-30.5)+(17-30.5)+(36-30.5)+(10-30.5)+(21-30.5)+(33-30.5)+(36-30.5))/(9)

Simplify it:


s^2=130.0555

Now, we need to use the next formula to find the standard deviation:


s=\sqrt{(\Sigma(x-x^-)^2)/(n-1)}

Then:


s=\sqrt{((38-30.5)^2+(45-30.5))^2+(27-30.5))^2+(42-30.5))^2+(17-30.5))^2+(36-30.5))^2+(10-30.5))^2+(21-30.5))^2+(33-30.5))^2+(36-30.5))^2)/(9)}

Then, the standard deviation is:


s=11.40419

User Bikash
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