Note: Your ? value should be .3 because each probability will then add to 1.
To find the mean:
SUM [x * P(x)]
Multiply each x by its respective probability P(x). Add together for a total. This will be your mean.
To find variance:
SUM [x^2 * P(x)] - mean^2
Square each x. Multiply each squared x by its respective probability P(x). Add together for a total. Square the mean. Subtract the squared mean from the total. This will be your variance.
To find standard deviation:
Take the square root of the variance.
Hopefully, this information will help you with other problems of this type.
Calculate the expected value and standard deviation of X, the number of on the job accidents:
Accidents 0,1 2 Probability .5, ?, .2
P(X=1) =
E(x) = µx =
Standard deviation =
1 answer
1 answer