An attendant at a car wash is paid according to the number of cars that pass through. Suppose that following payments are made with the following probabilities: Payment Probability $7 0.18 $9 0.08 $11 0.09 $13 0.16 $15 0.08 $17 0.41 Find the standard deviation of the attendant's earnings.

And we can find the second moment with this formula:

And replacing we got:

And we can find the variance like this:

And the deviation would be:

Step-by-step explanation:

For this case we have the following dataset given:

Payment     $7     $9     $11    $13    $15  $17

Probability 0.18  0.08  0.09  0.16  0.08   0.41

For this case we can calculate the mean with this formula:

And replacing we got:

And we can find the second moment with this formula:

And replacing we got:

And we can find the variance like this:

And the deviation would be:

step-by-step explanation:

mean or average is 40.6