There are 20 identical looking packets of white powder. 8 of them contain cocaine and 12 do not. Four of the packets are randomly selected. Let X equal the number of the selected packets which contain cocaine. a. How many possible ways are there to select the 4 out of 20 packets (order does not matter) without replacement? b. What is the probability that X = 0 c. What is the probability that X=4?
There are 20 identical looking packets of white powder. 8 of them contain cocaine and 12 do not. Four of the packets are randomly selected. Let X equal the number of the selected packets which contain cocaine. a. How many possible ways are there to select the 4 out of 20 packets (order does not matter) without replacement? b. What is the probability that X = 0 c. What is the probability that X=4?
A First Course in Probability (10th Edition)
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Chapter1: Combinatorial Analysis
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Transcribed Image Text:**Problem Statement:**
There are 20 identical looking packets of white powder. 8 of them contain cocaine and 12 do not. Four of the packets are randomly selected. Let \( X \) equal the number of the selected packets which contain cocaine.
**Questions:**
a. How many possible ways are there to select the 4 out of 20 packets (order does not matter) without replacement?
b. What is the probability that \( X = 0 \)?
c. What is the probability that \( X = 4 \)?
d. What is the probability that \( X > 3 \)?
e. What is the expected value of \( X \)?
f. What is the standard deviation of \( X \)?
g. What is the probability that \( X \) is smaller than its expected value?
h. What is the probability that \( X = 5 \)?
_Add any comments below._
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Transcribed Image Text:7.
DETAILS
a. How many possible ways are there to select the 4 out of 20 packets (order does not matter) without replacement?
b. What is the probability that X = 0
c. What is the probability that X=4?
d. What is the probability that X > 3?
e. What is the expected value of X?
f. What is the standard deviation of X?
MY NOTES
There are 20 identical looking packets of white powder. 8 of them contain cocaine and 12 do not. Four of the packets are randomly selected. Let X equal the number of the selected packets which
contain cocaine.
g. What is the probability that X is smaller than its expected value?
h. What is the probability that X = 5?
Add any comments below.
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