Posted by George on Thursday, October 11, 2012 at 12:04pm.
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 =

Stats  MathGuru, Thursday, October 11, 2012 at 7:10pm
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.
Answer This Question
Related Questions
 Statistics  I have a problem I need some help on. I have answered parts. Any ...
 statistics  The number of accidents per week at a hazardous intersection ...
 Statistics  The number of traffic accidents per day on a certain section of ...
 probability  There is a .97 chance that no accident will occur during any ...
 Math  The data shows the total number of employee medical leave days taken for ...
 Statistics  I have a problem I need some help on. I answered some. For many ...
 Math  The number of accidents that occur at the intersection of Pine and Linden...
 MATH  The number of accidents that occur at the intersection of Pine and Linden...
 Math  The number of accidents that occur at the intersection of Pine and Linden...
 math157  The number of accidents that occur at the intersection of Pine and ...
More Related Questions