A professor gives a weekly quiz with varying numbers of questions and uses a randomization device to decide how many questions to include. Let the random variable X = the number of questions on an upcoming quiz.
The probability distribution for X is given in the following table, but one probability is missing. What is the probability that X = 30?
|
No. of Questions, X
|
10
|
15
|
20
|
25
|
30
|
|
Probability
|
.05
|
.20
|
.50
|
.15
|
?
|