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The mean is: Find the mean and standard deviation for the number of sleepwalkers in group five.

The mean is: Find the mean and standard deviation for the number of sleepwalkers in-example-1

1 Answer

5 votes

As given by the question

There are given that the probability distribution and the value of x

Now,

First find the value of mean:

So,

The value of mean will be:


\operatorname{mean}=0*0.193+1*0.354+2*0.304+3*0.112+4*0.034+5*0.003

Then,

Solve the above expression:


\begin{gathered} \operatorname{mean}=0*0.193+1*0.354+2*0.304+3*0.112+4*0.034+5*0.003 \\ \operatorname{mean}=0+0.354+0.608+0.336+0.136+0.015 \\ \operatorname{mean}=1.449 \end{gathered}

Hence, the value of the mean is 1.449.

Now,

Find the standard deviation:

So, from the formula of standard deviation


\text{Standard deviation=}\sqrt[]{\sum^(\infty)_(n\mathop=0)(x-mean})^2* P(x)

Then,


\begin{gathered} \text{Standard deviation=}\sqrt[]{\sum^(\infty)_{n\mathop{=}0}(x-mean})^2* P(x) \\ =\sqrt[]{(0-1.449)^2*0.193+(1-1.449)^2*0.354+(2-1.449)^2*0.304+(3-1.449)^2*0.112+(4-1.449)^2*0.034+(5-1.449)^2*0.003} \end{gathered}

Then,


\begin{gathered} =\sqrt[]{(0-1.449)^2*0.193+(1-1.449)^2*0.354+(2-1.449)^2*0.304+(3-1.449)^2*0.112+(4-1.449)^2*0.034+(5-1.449)^2*0.003} \\ =0.405+2.123+0.092+0.27+0.221+0.0378 \\ =3.1488 \end{gathered}

Hence, the value of the standard deviation is 3.1488.

User Belyid
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