-1
votes
1answer
35 views

Odds to guess a 32 byte value [closed]

I have 1,000,000 records, and each is assigned a 32 byte (3.4E+38) random value. What is the likelihood to guess one of the random values? Context This comes up in information security context: ...
1
vote
3answers
33 views

Problematic Permutation Problem

i see a problem without any definition. would you please help me? i want to calculate the number of permutations of 1,2,...,1392 that 696 numbers be in the natural positions (from all numbers, 696 ...
0
votes
3answers
32 views

DNA Sequence Distinct Way

we know The genetic code is based on the four nucleotides adenine (A), cytosine (C), guanine (G), and thymine (T). These are connected in long strings to form DNA molecule. with three A, one C, two G ...
0
votes
1answer
27 views

How to calculate the HHG (Heller Heller Gorfine) correlation

HHG (A consistent multivariate test of association based on ranks of distances) is introduced in: Heller, R., Heller, Y., & Gorfine, M. (2012b). A consistent multivariate test of association ...
0
votes
0answers
24 views

Comparing test statistics and/or $p$-values from multiple permutation (Mantel) tests on non-independent data

I am comparing the relationship between genetic and geographic distance of individuals in a wild animal population. The hypothesis is that individuals with higher genetic relatedness establish home ...
0
votes
1answer
24 views

Permutations of a sequence of words

I've been given a question in class and I just wanted to confirm the answer ...
0
votes
2answers
143 views

Permutations of a letter sequence

I have been given a question about (i think) permutations, it asks to find how many x letter sequences can be made out of a word. I am getting confused because it first asks how many different ...
1
vote
1answer
35 views

Largest Number Drawn - Why are These Approaches Not Equivalent?

Here's the question: Four numbers are drawn at random from a box of ten numbers 0, 1, ..., 9. Find the probability that the largest number drawn is a six if the draws are made with replacement. The ...
0
votes
3answers
482 views

A bowl contains 10 red balls and 10 blue balls, A women selects ball at random without looking?

How can we solve this question ? A bowl contains $10$ red balls and $10$ blue balls, and a women picks up balls from the bowl, at random, without looking. A) How many balls must she pickup in ...
1
vote
2answers
961 views

In how many ways can 20 identical balls be distributed into 4 distinct boxes subject?

I was practicing math exercises on text book and i got stuck in this question ? ...
0
votes
2answers
31 views

Partioning/Enumeration

How many ways can one distribute A) 15 Balls into 3 bags. Both bag and balls are distinct (labelled) and each bag must contain at least one ball. B) 10 balls into 3 bags. again both bag and balls ...
2
votes
0answers
65 views

How many different ways can 10 octupuses touch legs?

There are 10 octopuses (octopi?). Each octopus has 8 legs. Legs on an octopus can only touch touch legs on other octupuses. Assuming each leg touches exactly 1 other leg, how many different ...
1
vote
2answers
151 views

combination and permutation !!!!

I have 3 questions that i had a try to do but i didn't understand them could anybody please help me to solve these questions. For Q1 i know how to use the multiplication counting procedures for a) i ...
2
votes
2answers
77 views

What is the probability no slots contain more than two balls given I am trying to sort 5 balls into 6 slots?

I am having a difficult time understanding how to approach this problem. Suppose I have $6$ total slots and $5$ balls. Now, I assign the balls at random to the slots. What is the probability that no ...
0
votes
1answer
111 views

Hypothesis testing for equivalence of two arrangements

I have two arrangements(i.e. permutations) of numbers. First one is the target/real arrangement. Second, is the observed arrangement. e.g. Target := 1,2,3,4,5,6,7 Observed := ...
1
vote
1answer
978 views

In a standard deck of 52 cards, how many different 7 card hands are there in which 3 cards are hearts and the other 4 are of different suits?

I know there are 13 cards in each suit, so that would mean I needed 3 of the 13 hearts or 13 P 3, then the other 4 would need to be out of 39 so it would be 39 P 4 but I don't know where to go from ...
0
votes
1answer
23 views

Help with Discrete Probability

I'm trying to show statistics related to combinations of discrete variables. I have a feeling what I need to do is quite simple but I can't for the life of me remember the correct formulas to achieve ...
0
votes
1answer
148 views

Probability of the sum of two drawn cards being less than 11?

An Ace has a value of 11 in this problem, and a face card has a value of 10. Thus, my idea for solving this problem was to separate the problem into 7 different cases (drawing a 2 first, 3 first, 4 ...
0
votes
0answers
9 views

transpositions of a set - terms and notations

I have 8 elements that are sequentially are connected as below making a circle : P -> R -> G -> B -> O -> S -> C -> D -> P We have to list all possible 5-transposition orders i.e. dO : G -> B -> O ...
0
votes
1answer
187 views

Calculating the expected profit with Probability A level maths CIE

Company sets up display of 20 fireworks! for each firework, the probability that it fails is 0.05,independently of other fireworks the probability that more than 1 firework fails is 0.264 the 20 ...
0
votes
3answers
79 views

Is this a Combination problem?

In how many ways can the letters of the word ADRIENNE be arranged so that no two vowels are together? Simplify your answer. My answer is the following: $\dfrac{8!}{2!2!} - \dfrac{4!}{2!} \cdot ...
0
votes
0answers
36 views

Calculating the probabilities of different lengths of repetitions of numbers of length 6

This question is similar to the question I asked here: Calculating the probabilities of different lengths of repetitions of numbers of length 4 except now I'm having problem with numbers of length 6. ...
1
vote
2answers
42 views

Number of length-five words

How many length-five words can be written using two A's, two T's and one E? Why is it not $\binom5 2 \times\binom 5 2 \times \binom 5 1$? Is it $ \binom 5 3 = 10$?
3
votes
2answers
35 views

Number of Strings with two specific letters

How many ways can you construct a string four letters (from 26 alphabet characters) that have both the letters j and k in them?
1
vote
2answers
44 views

Is my answer to this combinatorics question correct? Counting the number of functions where $F(a) = F(b)$?

Let $A = \{a, b, c, d, e, f\}$ and $B = \{1, 2, 3, 4, 5\}$. How many functions $F$ from $A$ to $B$ are there such that $F(a) = F(b)$. I looked at it like this: If $F(a)$ and $F(b)$ are equal, that ...
2
votes
1answer
77 views

Is this a Permutation or a Combination?

To win a lottery, you must pick the winning 3 numbers from the integers 1-9 (no repeat numbers). What is the probability of winning the lottery by choosing the correct 3 numbers? I think its a ...
1
vote
3answers
2k views

Combinatorics and Probability Problem

The problem I am working on is: An ATM personal identification number (PIN) consists of four digits, each a 0, 1, 2, . . . 8, or 9, in succession. a.How many different possible PINs are there if ...
0
votes
1answer
295 views

Probability of A Specific Type of Experiment Occuring

The problem is: An experimenter is studying the effects of temperature, pres-sure, and type of catalyst on yield from a certain chemical reaction. Three different temperatures, four different ...
8
votes
3answers
2k views

How would I figure out how many anagrams of mississippi don't contain the word psi?

I'm really confused how I'd calculate this. I know it's the number of permutations of mississippi minus the number of permutations that contain psi, but considering there's repetitions of those ...
3
votes
1answer
89 views
1
vote
2answers
52 views

How would I determine the number of solutions for the sum of this number?

We're given the following equation: $$x_1 + x_2 + x_3 + x_4 + x_5 = 20$$ I know that the simple amount of solutions to this is $\binom{5+20-1}{5-1}$, but for the following questions I'm slightly ...
1
vote
1answer
64 views

How would I go about solving this statistics question on permutations?

Columba has two dozen each of n different coloured beads. If she can select 20 beads (with repetition of colors allowed) in 230,230 ways, what is the value of n? I'm trying to figure it out, ...
1
vote
1answer
455 views

How do I find the number of bit strings with 3 consecutive 0s in a bit string of length n?

Say n is 8. How would I ever solve this problem? I've Googled around and searched this site but I haven't come up with much. I'm not even looking for the answer necessarily, just the process by ...
1
vote
2answers
889 views

How to calculate the expected frequency of a pattern?

I'm working on a problem to find the expected frequency of a pattern. Say there is a sequence of alphabets - A, B, C and D. The sequence is: ABDACDBADA. I want to find the expected frequency of a ...
2
votes
0answers
295 views

sum with permutations

Let $a$ be vector in $R^{2m}$. And let $S_{2m}$ be group of all permutations on the set $\{1,\dots,2m\}$. I would like to calculate $$ \sup_{\pi\in S_{2m}}\sum_{d(\sigma, ...
4
votes
1answer
279 views

question involving Markov chain

Let $S_{2m}$ be the group of all permutations $\pi$ of $\{1, 2, \ldots, 2m\}$. The following transition kernel $S$ generates the random transposition walk $$ Ch(\pi, \pi')= \begin{cases} \frac{1}{2m} ...
0
votes
1answer
1k views

Combinations and Permutations Question

I am sitting my A level exams (MEI) and I was looking through the S1 past papers and I encountered this question in the January 2010 paper: Three prizes, one for English, one for French and one ...