Recent content by rhyno89

ok thanks that makes a lot of sense... i think that is similar to what i initially tried to do and just got confused along the way... my only question about that is what property of the F distribution results in being able to rewrite X with df 1 / Y with df 2 as X/2Y and since u can do that...

Ok i understand that part...i can't use the additive property because I am not adding three different independent random variables, I am merely multiplying the one that I do have by 3. Since I can't use 3 df i have to still use the 1 and 2 respectively. It seems that a logical attempt would...

since there is an additive property with independent chi square distributions...could i treat the 3X as simply X+X+X and get a chi square random variable with 3 degrees of freedom?

Homework Statement If X and Y are independent chi square random variables with degrees of freedom of 1 and 2 respectively, then W = 3X/Y with P(W >= q) .25 holds for what q value Homework Equations The Attempt at a Solution So I know that the result of two chi square...

what i did was just combine the means since they are independent...resulting in a total mean of 8 minutes. This resulting in a lambda of 1/8 and therefore a variance of 1/64. Finally it would have a pdf of 1/64e^-x/64... im pretty sure that's right but can anyone clarify?

Homework Statement A concession stand serves customers with each customer starting as soon as the prior one finishes. The wait times are from an exponential distribution with mean = 2 minutes. Therefore the Total time is the summation of xi for i 1 to 4. Find the mean , variance and...

Homework Statement The cross sectional area of a tube is u = 12.5 and SD = .2. When the area is less than 12 or greater than 13 it won't work. They are shipped in boxes of 1000, determine how many per box will be defective Homework Equations The Attempt at a Solution So I think...

So my book merely mentions that this holds as a result of the central limit theorem for values of lambda greater than 10, but ideally greater than 32. Anyway I was wondering if anyone knew this actual proof as I am interested in seeing it step by step and I could not have found it anywhere...

Homework Statement Suppose that 15 observations are chosen at random for the pdf f(Y) = 3y^2 on the interval 0 to 1. Let X denote the number that lie in the interval (.5,1). Find E(X) Homework Equations The Attempt at a Solution Ok so to get the expected value u integrate the...

i thought i had to do something like that since it was an interval and not merely a finite set of numbers. This kinda seems like a pointless exercise since this would have me differentiating the cdf to get the pdf just to re integrate it and return it to the cdf plugging in the same numbers that...

Homework Statement For a given cdf: Fy(y) = 0 for y less than 0 = y^2 for the range 0 to 1 = 1 for all values greater than or equal to 1 the problem asks to find P(1/2 < Y < 3/4) first using the cdf and then using the pdf...

yea thanks i figured it out The first one is 6(1/6^3) The second is 6*5 * 3 different combos over 216 and the last one is 6*5*4/ 216

Homework Statement Roll a fair die three times Let X be the number of different faces shown all together ( X = 1,2,3 ) Find px(k) Homework Equations The Attempt at a Solution Alright so I kno that i need to get the individual probabilities of each outcome The first one where...

Homework Statement prove the following:A U (intersect from i = 1 to n of Bi) = intersect of i from 1 to n of (A U B) Homework Equations The Attempt at a Solution i started off trying to rewrite it and make it a bit more readable A U (Bi and Bi+1) = Bi+1 and (A U Bi) then...

Ok I think i can take it from here, thanks a lot you really saved me with this