Let Y1, Y2, …, Y4 be a random sample from a normal distribution with mean 10 years and
standard deviation 2.5 years. Find the following probabilities.
A. P(Y4 > 14 years)
B. P(Y1 + Y2 + Y3 + Y4 < 36 years)
C. P{(Y1 < 9 years) and (Y2 < 9 years) and (Y3 < 9 years) and (Y4 < 9 years)}
Note: B and C are asking different questions.
D. Find E(Y1 + Y32), the expected value of Y1 plus the square of Y3.

Let Y1, Y2, …, Y4 be a random sample from a normal distribution with mean 10...
Let Y1 N(1,1), Y2 N(2,2), and Y3 N(3,3) be independent random variables. Find a new random variable Y4 that is a function of Y1, Y2, and Y3 such that Y4 has a t-distribution with 2 degrees of freedom, and explain why it has that distribution. (To avoid confusion, the parameters in the normal distributions above are the mean and the standard deviation.)
15. (30 points) Let Y1 < Y2 < Y3 < Y4 be the order statistics of a random sample of size n = 4 from a distribution with p.d.f.f(x) 2x, 0 < x < 1, zero elsewhere. Evaluate E[Yalyj]. [Hint: First find the joint p.d.f. of Y3 and Y4, and then find the conditional p.d.f. of Y4 given Y3 y3]
15. (30 points) Let Y1
Let Y1< Y2< Y3< Y4< Y5 be the order statistics of n=5 independent observations from the exponential distribution with mean= 1. determine P(Y1>1) and find the pdf of Y5
Let Y1<Y2<...<Yn be the
order statistics of a random sample of size n from the distribution
having p.d.f f(x) = e-y , 0<y<, zero elsewhere. Answer the following
questions.
(a) decide whether Z1 = Y2
and Z2=Y4-Y2 are
stochastically independent or not. (hint. first find the joint
p.d.f. of Y2 and Y4)
(b) show that
Z1 = nY1, Z2=
(n-1)(Y2-Y1),
Z3=(n-2)(Y3-Y2), ....,
Zn=Yn-Yn-1
are stocahstically
independent and that each Zi has the exponential
distribution.(hint use change of variable technique)
Suppose Y1, Y2, Y3, Y4, Y5 is a random sample from a gamma
distribution where the shape parameter is known to be 2
and the scale parameter is unknown.
a) Show that
is a pivotal quantity.
b) Show that
is a pivotal quantity.
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Let Y1, Y2, . . . , Yn be independent random variables with Exponential distribution with mean β. Let Y(n) = max(Y1,Y2,...,Yn) and Y(1) = min(Y1,Y2,...,Yn). Find the probability P(Y(1) > y1,Y(n) < yn).
Sampling for Engineers Homework question 11.51 Suppose that Y1;Y2;Y3;Y4 denote a random sample from a Poisson(θ) distribution where (θ> 0) is an unknown parameter. Show all details to prove that Y bar is a (minimal) sufficient statistic for θ .
Let Y1, Y2, ..., Yn denote a random sample from an exponential distribution with mean θ. Find the rejection region for the likelihood ratio test of H0 : θ = 2 versus Ha : θ ≠ 2 with α = 0.09 and n = 14. Rejection region =
Let Y, Y2, Yz and Y4 be independent, identically distributed random variables from a population with mean u and variance o. Let Y = -(Y, + Y2 + Y3 +Y4) denote the average of these four random variables. i. What are the expected value and variance of 7 in terms of u and o? ii. Now consider a different estimator of u: W = y + y + y +Y4 This an example of weighted average of the Y. Show...
2. [x] Suppose that Y1, Y2, Y3 denote a random sample from an exponential distribution whose pdf and cdf are given by f(y) = (1/0)e¬y/® and F(y) =1 – e-y/0, 0 > 0. It is also known that E[Y;] = 0. ', y > 0, respectively, with some unknown (a) Let X = min{Y1,Y2, Y3}. Show that X has pdf given by f(æ) = (3/0)e-3y/º. Start by thinking about 1- F(x) = Pr(min{Y1,Y2, Y3} > x) = Pr(Y1 > x,...