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Heads occurs 15 times out of 20  Is it a fair coin? 
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#1
Feb2408, 03:40 PM

P: 3

1. The problem statement, all variables and given/known data
I have to answer this question by using references to expectation and probability as well as any other relevant considerations. My textbook says that 96% of the time, the number of heads in 20 flips will be between 6 and 14 inclusive. How do I prove this? 


#2
Feb2408, 08:30 PM

P: 1,875

Do you know about the standard deviation?



#3
Feb2508, 01:24 AM

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PF Gold
P: 9,225

Anyway, if you want to prove that 96% figure, you have to add up the probabilities for "exactly 6", "exactly 7" and so on. Do you know how to calculate those? 


#4
Feb2508, 05:28 AM

P: 86

Heads occurs 15 times out of 20  Is it a fair coin?



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