Questions tagged [statistics]
Mathematical statistics is the study of statistics from a mathematical standpoint, using probability theory and other branches of mathematics such as linear algebra and analysis.
11,536
questions with no upvoted or accepted answers
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MLE question given bionomial
I'm not exactly sure how to go about this question.
Among $N$ $i.i.d.$ observations on a $Binomial(2,p)$ random variable, $N_0$ takes on the value 0, $N_1$ takes on the value 1 and $N_2$ take on the ...
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Binomial distribution question - solving for p
If $X \sim \operatorname{Binomial}(2,p)$, find a value of p for which $Pr(W=4)=0.3432$, where $W=(X+1)^2$
My thought process:
Find $X$ when $W=4$,
$$4=(X+1)^2$$
Therefore $X=1$
Then solve ...
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1
answer
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Expectation of Matrix's Determinant
I have an issue about find expectation of deteminant
Give a symmetric matrix, It has tree entries which is uniform random variable U(-60;60). Find expectation of Matrix's determinant
Please help me. ...
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How to find the percentage of $\bar{X}\pm S$?
How to find the percentage of $\bar{X}\pm S$ in the table
The solution is given as
then
the percentage is
My question is where does the equation
come from?
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172
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MLE of a Normal Distribution
Consider independent random variable $Y_1,Y_2,\dots, Y_n$ and known real numbers $x_1,x_2,\dots x_n$. The distribution of $Y_i$ is Normal with mean zero and variance $\sigma^2/x_i^2$, where $\sigma^2$ ...
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1
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57
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How would one find the sum of the following question using poisson properties?
I don't really have any idea how to approach this question. I can't manipulate it to resemble poisson.
$\sum_{x=0}^{\infty}\frac{2^x}{x!}$
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1
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113
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How do I calculate mean and sd with only such information provided?
Question
If ππ=ππ+0.25ππ and ππ and ππ are independent random variables that are formulated to be normally distributed with ππβΌππ(πππ₯π₯,πππ₯π₯) and ππβΌππ(πππ¦π¦,πππ¦π¦),
(a)...
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2
answers
85
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Figuring out a conditional probability question with an answer that doesnβt make sense
Here is the question:
A contractor is hired for the job of paving streets and roads, in the end if the quality of pavement is approved by quality assessments, the contractor's work is accepted.
We ...
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1
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What is the definition of 1 standard deviation.
I know what the standard deviation is. I know about the 68β95β99.7. My question is what is the definition of 1 (just 1) standard deviation. Why is it 68 and not 70. Is it because that's where the ...
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votes
1
answer
144
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Statistics: Finding mean lifetime with given lifetimes
Given:
$P(X>5) = .7$
$P(X>15) = .343$
$P(X < 2.5) = .8367$
Find the mean lifetime.
I tried finding $\mu = 1/\lambda$, but that wasn't the correct answer. I'm not sure what equation to ...
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1
answer
112
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What is the t-score for the relationship between X & Y
The police chief is concerned about alarm systems degrading in city buildings and failing to operate. Using a sample of 100 alarms in operation the previous year, the police department regresses ...
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1
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146
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How do I determine percentages using the mean and standard deviation?
There are 80 terms, measured in seconds.
The standard deviation is 77.96433 (sec).
The mean is 267.2375 (sec).
What percentage are over 180 seconds?
What percentage are between 210 seconds and 300 ...
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votes
1
answer
40
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Finding this probability, I need some explanation.
If green and yellow seeds per plants are crossed and $15$ seeds are obtained calculate the probability of getting $(0,1,2,....15)$ green seeds. Green is a dominant and hybrid gene, yellow is a ...
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1
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279
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Probability interval for a cost related to a Poisson random variable.
For a certain section of pine forest, the number of diseased trees per acre, Y, has a poisson distribution with mean of 10. The diseased trees are sprayed with an insecticide at a cost 3 dollars per ...
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2
answers
987
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confused about meaning of a expectation of a function
https://en.wikipedia.org/wiki/Bias%E2%80%93variance_tradeoff#Derivation
well,in the "Derivation" part of the wiki link.
i don't figure out why $E(f)=f$, does it imply that the function $f$ is ...
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How many unique combinations are possible if category contents are limited?
I'm working on a personal project and came across an algorithm problem which stumped me. I need to know whether a user has given my program the correct parameters to create the amount of random ...
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