Recent content by sanctifier

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    Statistics: What is the probability of type I error?

    Help! Does anyone know the correct solution?
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    Probability: What is the conditional distribution of X?

    Thank you for your insistent reply. As you suggested, P(X=x \cap X+Y=m)=P(X=x \cap Y=m-x)= \frac{\lambda_1^x}{x!}e^{-\lambda_1} *\frac{\lambda_2^{m-x}}{(m-x)!} e^{-\lambda_2}=\lambda_2^m e^{-\lambda_1-\lambda_2} (\frac{\lambda_1}{\lambda_2})^x \frac{1}{m!} {m \choose x} P(X+Y=m) =...
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    Probability: What is the conditional distribution of X?

    To (1) Did you mean P(X=x|X+Y=m) = \frac{P(X=x \bigcap X+Y=m)}{P(X+Y=m)} To (2) Then what shall I do if the standard means doesn't work?
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    Probability: What is the conditional distribution of X?

    This is correct. kduna, thank you a lot!
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    Probability: What is the conditional distribution of X?

    Homework Statement If random variables X and Y are independent and both belong to Possion distribution of parameters \lambda_1 and \lambda_2 , then what is the conditional distribution of X when the condition X + Y = m is given? Homework Equations Possion distribution of...
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    Probability: What is the probability of drawing items from containers?

    Ray is professional. Indeed, I should use some notation to explicitly describe the answer. You have given the correct answer, it should be P(F|U) = \frac{P(F \cap U)}{P(U)} = \frac{\sum_{i=1}^3 P(F \cap U | B_i) P(B_i)}{\sum_{i=1}^3 P(U|B_i) P(B_i)} where P(U) = \frac{1}{3}( \frac{7}{10}...
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    Probability: What is the probability of drawing items from containers?

    \frac{7}{10} \frac{6}{9} denotes the case the 1st drew product is unflawed and the 2nd drew product is also unflawed. \frac{6}{9} means after the 1st withdrawal there are 9 products left in the Box 1 and 6 of the left products are unflawed
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    Probability: Is the manager telling the truth?

    Homework Statement The manager of a factory proclaims 99% of the products manufactured in his factory are unflawed. If we draw 50 products from 5000 products and find 2 of 50 are flawed, then how do we know the manage is telling the truth? Homework Equations Nothing special. The...
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    Probability: What is the probability of drawing items from containers?

    Homework Statement There are 3 boxes containing some products of same type. Box 1 contains 10 products and 3 of them are flawed. Box 2 contains 15 products and 7 of them are flawed. Box 3 contains 25 products and 5 of them are flawed. Randomly choose one box from the 3 then draw...
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    Statistics: What is the probability of type I error?

    Homework Statement X is a random variable of binomial distribution of parameter n=10 and unknown parameter p. Hypotheses are given as follows: H_0 \;\; : \;\; p=0.6 H_1 \;\; : \;\; p \neq 0.6 Suppose rejection region for H_0 is \{X \leq 1\} \cup \{X \geq 9\} Question 1: What is...
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    Probability: What are E(x) and Var(x) of this specific X

    Actually, I have no instructor to consult. I learned the probability and statistics by reading textbooks and doing exercises in the ends of each chapters. This may be the only place I can acquire the correct answers with the help of kind people like you and Ray. Current answer is good enough...
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    Statistics: What is the efficient estimator of sigma^2?

    Thank you for reply. Sorry for causing confusion, "σ is given but unknown" just means although σ remains in the formula, it acts like the unknown variable and needs to be estimated through the known values of X_{1},\; X_{2},\;\;...,\;\; X_{n} . Thank you for mentioning the M.L.E. Actually...
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    Statistics: How to prove the consistent estimator of theta?

    Thank you for your replay, Ray. Actually, the moment estimator denotes the method of moments estimator, you can find it here: http://en.wikipedia.org/wiki/Method_of_moments_(statistics ) What I’m concerning is the estimator found by using method of moments. Answer 2 is wrong. It...
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    Statistics: How to prove the consistent estimator of theta?

    Homework Statement If the probability density function (p.d.f.) of the random variable X is f(x| \theta ) =\begin{cases} \frac{1}{3\theta} & 0 < x \leq 3\theta \\0 & otherwise\end{cases} Where \theta > 0 is an unknown parameter, and X_1, X_2 … X_n is a sample from X where n > 2...
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