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

A

x P(x)

25 0.1

50 0.6

75 0.1

100 0.2

B

x P(x)

25 0.1

50 0.6

75 0.1

100 0.4

C

x P(x)

25 0.1

50 0.6

75 0.1

100 0.6

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

C, A or B

b.Using the correct probability distribution, find the probability thatxis:(Round to 1 decimal place.)

1.Exactly 75 =

2.No more than 75 =

3.More than 75 =

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

1.Mean =

2.Variance ²=

3.Standard deviation =