0
votes
0answers
28 views

Problem calculating the average power of a vector?

I am calculating the average power of a vector. I would like to compare the final expression with the simulation. However, they are not equal. Please help me to point out which steps are wrong. Thank ...
1
vote
0answers
48 views

Extension to Classical Coupon Collectors Problem

If there's n different coupons. Instead of ordering coupons one-by-one until you collect all n coupons as in the traditional 'Coupon Collector Problem', what if the coupons came in packs of m coupons. ...
0
votes
0answers
48 views

Extension to the Coupon Collector Problem

If there's n different coupons. Instead of ordering coupons one-by-one until you collect all n coupons as in the traditional 'Coupon Collector Problem', what if the coupons came in packs of m coupons. ...
4
votes
2answers
264 views

Expected Value of Local Maxima and Local Minima

Recently I came across this question: Given a random permutation of integers 1, 2, 3, …, n with a discrete, uniform distribution, find the expected number of local maxima. (A number is a local maxima ...
0
votes
2answers
35 views

Random number x probability in interval [0,10]

So lets say $x=10*rand()$, so x will be equal to a random number on the interval [0,10]. So what is the probability of $2x+1$ rounding to $5$. So one can come up with $4.5<=2x+1<5.5$. Is that ...
0
votes
1answer
69 views

Covariance problem.

The experiment is a three hat experiment with the following probabilities: $\frac15$ for $(1,2,3)$, $(1,3,2)$, $(2,1,3)$ and $(3,2,1)$, and $\frac1{10}$ probability for $(2,3,1)$ and $(3,1,2)$. Find ...
1
vote
1answer
100 views

Expected value vs using method of indicator

I am having a hard time understanding the difference between getting the Expected value by finding the mean E(X)=np and using the method of indicator to find the expected value. For example if we ...
1
vote
1answer
29 views

Calculating the distribution of random variables and the expected value/mean of a random variable?

I'm not sure whether or not I picked the correct distribution method and calculated the distribution correctly. Here is the problem: Consider Bob, an absent-minded student. Bob has a set of 5 ...
0
votes
0answers
32 views

Question about a random variable/probability example

Say $X_1$ is a random variable equivalent to a flip of a fair six sided dice. say $X_2$ is also a random variable equivalent to a flip of a fair six sided dice. and say that $X = X_1 + X_2$ How ...
1
vote
1answer
104 views

Bernoulli distribution vs the probability mass function

What is the difference between the two? They seem to mean the same thing to me. The probability mass function can be used to find the probability of getting a tail from a coin flip: X{1 ...
-2
votes
1answer
25 views

Discrete random variables problem

I don't know how to answer the following question: Argue that if $X$ and $Y$ are nonnegative random variables, then $E[\max(X,Y)] \leq E[X] + E[Y]$
0
votes
3answers
41 views

Random variable $X$ inducing a distribution on $V$

I have been learning about discrete probability and found a somehow confusing (to me) definition of distribution of a random variable $X$ on a set $V$. The definition of a Random variable $X$: $$ ...
1
vote
3answers
154 views

Finding unknown values from discrete probabilities.

(I am confused here with the limits. It says x = 0,1,2,3... So what is my end limit her? Thanks.)
1
vote
0answers
50 views

Proving a variable as discrete random (confusing question)

A box contains 3 white and 3 black marbles. In a game, 3 marbles are randomly selected from the box. The score (X) is equivalent to the getting of 10 white marbles. Show that X is a discrete random ...
0
votes
1answer
105 views

Expected value of index of the minimum element in an array

I'm stuck the following assignment: What is the expected value of the index of the minimum element in an array of n distinct integer that are randomly ordered? I think it should be something like: ...
0
votes
1answer
70 views

Expected number of Diamonds in a 5-card hands

What would be the correct answer for expected number of diamonds in a 5-card hands? I am thinking as follow: Let $X_i = 1$ if the i-th card is diamond, or $0$ otherwise. $X_i = (1 \times P($i-th ...
0
votes
1answer
41 views

discrete random variable PMF

suppose You rented a house and realtor gave you 5 keys, one for each of the 5 doors of house. unfortunately all keys look identical. so to open the front door, you try them at random. => Find the ...
1
vote
1answer
73 views

Ignoring $\max$ for discrete random variables

Let $X,Y,Z$ be independent discrete random variables with $X\sim\text{Bin}(6,7/8),$ $Y\sim\text{Bin}(5,7/8)$ and $Z\sim\text{Geo(1/4)}$. Futhermore let $M:=\max(X+Y,Z)$. Compute ...