Question

Three tables listed below show random variables and their probabilities. However, only one of these is actually a probability distribution.

 

A			B			C
x	P(x)		x	P(x)		x	P(x)
25	0.6		25	0.6		25	0.6
50	0.1		50	0.1		50	0.1
75	0.1		75	0.1		75	0.1
100	0.4		100	0.2		100	0.6

 

a. Which of the above tables is a probability distribution?

 

 (Click to select)  B  A  C 

 

b. Using the correct probability distribution, find the probability that x is:  (Round the final answers to 1 decimal place.)

 

1.	Exactly 50 =
2.	No more than 50 =
3.	More than 25 =

 

c. Compute the mean, variance, and standard deviation of this distribution. (Round the final answers to 2 decimal places.)

 

1.	Mean µ
2.	Variance σ2
3.	Standard deviation σ