Question
A random experiment of tossing a die twice is performed. Random variable X on this
sample space is defined to be the sum of two numbers turning up on the toss. Find the
discrete probability distribution for the random variable X and compute the corresponding
mean and standard deviation.
sample space is defined to be the sum of two numbers turning up on the toss. Find the
discrete probability distribution for the random variable X and compute the corresponding
mean and standard deviation.
Answers
Damon
36 possibilities
number of times sum
1 * 2 = 2
2 * 3 = 6
3 * 4 = 12
4 * 5 = 20
5 * 6 = 30
6 * 7 = 42
5 * 8 = 40
4 * 9 = 36
3 * 10= 30
2 * 11= 22
1 * 12= 12
-----------
36 and 252
mean = 252/36 = 7
go ahead and compute sigma
number of times sum
1 * 2 = 2
2 * 3 = 6
3 * 4 = 12
4 * 5 = 20
5 * 6 = 30
6 * 7 = 42
5 * 8 = 40
4 * 9 = 36
3 * 10= 30
2 * 11= 22
1 * 12= 12
-----------
36 and 252
mean = 252/36 = 7
go ahead and compute sigma
Paul
A dictionary contains 80,000 words, of which a certain student knows 30,000. If 100 of the 80,000 words are selected at random from the dictionary without replacement, find the probability:the student knows exactly 40 of the 100 words