In the accompanying table the random variable x represents t
In the accompanying table, the random variable x represents the number of televisions in a household in a certain country. Determine whether or not the table is a probability distribution. If it is a probability distribution, find its mean and standard deviation.
x,P(x)
0,0.03
1,0.14
2,0.24
3,0.27
4,0.18
5,0.14
If the table is a probability distribution, what is its mean? Select the correct choice below and fill in any answer boxes within your choice.
Its mean is _______?
OR
The table is not a probability distribution?
If the table is a probability distribution, what is its standard deviation? Select the correct choice below and fill in any answer boxes within your choice.
standard deviation is _______?
OR
The table is not a probability distribution.
Solution
Consider:
it is a probability distirbution, as the probabilities sum up to 1.
Thus,      
       
 E(x) = Expected value = mean =    2.85   [ANSWER]
Var(x) = E(x^2) - E(x)^2 = 1.7875
s(x) = sqrt [Var(x)] =    1.336974196   [ANSWER]
       
| x | P(x) | x P(x) | x^2 P(x) | 
| 0 | 0.03 | 0 | 0 | 
| 1 | 0.14 | 0.14 | 0.14 | 
| 2 | 0.24 | 0.48 | 0.96 | 
| 3 | 0.27 | 0.81 | 2.43 | 
| 4 | 0.18 | 0.72 | 2.88 | 
| 5 | 0.14 | 0.7 | 3.5 | 

