How to Calculate the Mean in a Probability Distribution
- 1). Write down the variable and the probability of the variable to occur in the form of a table. For example, the number of shirts sold by a store can be described by the following table where "x" represents the number of shirts sold every day and "P(x)" represents the probability of each event.
x P(x)
150 0.2
280 0.05
310 0.35
120 0.30
100 0.10 - 2). Multiply each value of x with the corresponding P(x) and store the values in a new column. For example:
x P(x) x*P(x)
150 0.2 30
280 0.05 14
310 0.35 108.5
120 0.30 36
100 0.10 10 - 3). Add the result from all the rows of the third column in the table. In this example, arithmetic mean = 30+14+108.5+36+10 = 198.5.
For the example, arithmetic mean gives an average value for the total number of shirts sold on daily basis.
Source...