8767: Q60

Forum for the GRE subject test in mathematics.
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YKM
Posts: 45
Joined: Mon Aug 08, 2011 10:25 am

8767: Q60

Post by YKM » Wed Aug 24, 2011 5:27 am

Q60:

A fair die is tossed 360 times. The probability that a six comes up on 70 or more of the tosses is?

Answer C: between 0.02 and 0.16.


Anyone knows the trick here without using calculator?

Thanks

hadimotamedi
Posts: 34
Joined: Thu Dec 30, 2010 4:36 am

Re: 8767: Q60

Post by hadimotamedi » Wed Aug 24, 2011 7:26 am

The involved distribution is the Bernoulli trial, with the following data :
n=360
k=1/6
For large n, use normal distribution to estimate it with :
µ = np
σ^2 = npq
Then use Chebyshev inequality for find an estimate of the engaged probability.

YKM
Posts: 45
Joined: Mon Aug 08, 2011 10:25 am

Re: 8767: Q60

Post by YKM » Thu Aug 25, 2011 2:19 am

Thanks



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