Thursday, September 1, 2011

What is the probability that Martha will fly to Las Vegas all four times

What is the probability that Martha will fly to Las Vegas all four times?
Martha is a flight attendant stationed in Denver. Her assignments are rotated randomly between flights to Dallas; Seattle; Portland; and Las Vegas. Consider a success being a trip to Las Vegas. What is the probability that Martha will fly to Las Vegas all four times?
Mathematics - 3 Answers
Random Answers, Critics, Comments, Opinions :
1 :
Hi, (¼)^4 = 1/256 I hope that helps!! :-)
2 :
4^4 = 1 in 256 or 0.39% chance
3 :
Let X be the number of flight Martha has to vegas. X has the binomial distribution with n = 4 trials and success probability p = 0.25 In general, if X has the binomial distribution with n trials and a success probability of p then P[X = x] = n!/(x!(n-x)!) * p^x * (1-p)^(n-x) for values of x = 0, 1, 2, ..., n P[X = x] = 0 for any other value of x. The probability mass function is derived by looking at the number of combination of x objects chosen from n objects and then a total of x success and n - x failures. Or, in other words, the binomial is the sum of n independent and identically distributed Bernoulli trials. X ~ Binomial( n , p ) the mean of the binomial distribution is n * p = 1 the variance of the binomial distribution is n * p * (1 - p) = 0.75 the standard deviation is the square root of the variance = √ ( n * p * (1 - p)) = 0.8660254 The Probability Mass Function, PMF, f(X) = P(X = x) is: P( X = 0 ) = 0.3164063 P( X = 1 ) = 0.421875 P( X = 2 ) = 0.2109375 P( X = 3 ) = 0.046875 P( X = 4 ) = 0.00390625 ← answer

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