An urn contains b black balls and w white balls. In each trial, a ball is drawn at
random from the urn and then is returned to the urn together with d additional balls
of of the same color as the drawn ball. Let Xi denote the color of the ball in the ith
trial.
a) Let X1, X2,.....Xn be a particular sequence of draws with exactly j black balls and
n-j white balls. What is the probability of this sequence of balls?
b) In 10 trials, what is the probability that the 5th draw is a black ball and the 10th
draw is a white ball?
c) In n trials, what is the expected number of times that a black ball is drawn?
Drawing balls
2013-05-10 9:16 pm
回答 (2)
2013-05-11 8:12 pm
✔ 最佳答案
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2013-05-11 5:43 am
An urn contains b black balls and w white balls. In each trial, a ball is drawn at
random from the urn and then is returned to the urn together with d additional balls
of of the same color as the drawn ball. Let Xi denote the color of the ball in the ith
trial.
a) Let X1, X2,.....Xn be a particular sequence of draws with exactly j black balls and
n-j white balls. What is the probability of this sequence of balls?
b) In 10 trials, what is the probability that the 5th draw is a black ball and the 10th
draw is a white ball?
c) In n trials, what is the expected number of times that a black ball is drawn?
random from the urn and then is returned to the urn together with d additional balls
of of the same color as the drawn ball. Let Xi denote the color of the ball in the ith
trial.
a) Let X1, X2,.....Xn be a particular sequence of draws with exactly j black balls and
n-j white balls. What is the probability of this sequence of balls?
b) In 10 trials, what is the probability that the 5th draw is a black ball and the 10th
draw is a white ball?
c) In n trials, what is the expected number of times that a black ball is drawn?
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