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?

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Chapter1: Combinatorial Analysis
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**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._
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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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.
ASK YOUR TEACHER
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. ASK YOUR TEACHER
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