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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.

Statistics is the science of the collection, organization, and interpretation of data. It deals with many aspects of data, which includes the planning of data collection in terms of the design of surveys and experiments. (From Wikipedia)

More specifically, mathematical statistics is the study of statistics from a mathematical standpoint, using probability theory as well as other branches of mathematics such as linear algebra and mathematical analysis. (From Wikipedia)

For questions which are more generally about collecting and treating data, it is advised that you post your question on Cross Validated and DSSE.

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Find $C$ such that $Ce^{(-4x^2-xy-4y^2)/2}$ is the joint pdf of a $2$-variable Gaussian

Find $C$ such that $$Ce^{(-4x^2-xy-4y^2)/2}$$ is a joint probability density of a $2$-variable Gaussian. If someone could give me a jumping off point, or a process as to how to go about this, I'd really appreciate it.
Damon Hillard
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Should we convert a grouped distribution to continuous if we have to find the median?

Today, in a math exam, I had to solve this question: In the following distribution, write the upper limit of the median class: $$\begin{array}{|c|c|}\hline…
Kartik
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Can't understand the parameters in adjusted R squared

I suppose this is a really stupid question, so please excuse me, but I can't get it. I'm using Simple Linear Regression (Least Squares) to find a line, fitting some points. The points are actually statistical data for sales each month. So their x…
Faery
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How to determine asymptotics properties for estimators

The question is as follows: If $X_i,\ldots,X_n$ are iid $N(\theta, \sigma^2)$, compare the asymptotic variance of the sample mean and sample median. Attempt: Would the asymptotic variance for the mean be the limit as $n$ approaches infinity of the…
lord12
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Is it plausible that multiple rankings can be averaged?

Say you have multiple advisors, each of which may have multiple domains of expertise. You rank the advisors in each domain, starting at $1$ and proceeding through $2, 3,$ etc. Since an advisor can have expertise in multiple domains, advisor Alice…
scanny
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Find the mean and median help!

I feel like there isn't much information, but the answer for the mean is 79. The median is said to not be able to be found. Can someone explain this? Thank you!
Helpappreciated111
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Comparing the width or variance of two distributions with uncertainty on variance estimate

So I have two probability distributions ,one from data and one from a model. They are not Gaussian shaped but skewed. I have measured their rms or width by finding the median and the 16% (lower limit) and 84% (upper limit) such that there is 68% of…
cinwick2321
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Probability of poisson distribution

Let $X$ be the number of cars per minute passing a certain point on Sunday from 8AM to 10AM. Assume that $X$ has poisson distribution with mean $5$. Find the probability observing $4$ or fewer car in any given minute? Here is what I got. Since this…
Diane Vanderwaif
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Estimating an unknown addition to data set

I have a data set with 11 points. The smallest point is 60, the largest is 122, and the average is 92.36. This is all that is known about the data set. I add one point (unknown size), such that there are now 12 data points. The smallest and largest…
mattk62586
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Distribution Significance

I am trying to determine if a distribution is significant given an overall population distribution. The population as a hole has a 4% distribution for my question. If a sub-group of my population has 17 out of 202 or 8.4% distribution is this a…
EpicOfChaos
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in statistics - why is type 1 error called type 1 and type 2 called type 2?

in order to remember stuff i need to understand their reason. Right now i cannot remember what is type 1 error and what is type 2 error why is the reason type 1 is false positive? i don't just want to remember without understanding thanks.
Jas
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Cohan's Kappa different class sizes

For my research I need to look at the Cohan's Kappa measure to find out if there is agreement. I asked four people to cluster 38 words and I got the following results: Person 1: 6 clusters Person 2: 7 clusters Person 3: 11 clusters Person 4: 9…
Pakspul
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If you choose an answer to this question at random, what is the probability that you will be correct?

Possible Duplicate: Does this question even have an answer? https://i.stack.imgur.com/GgxlS.jpg Question: If you choose an answer to this question at random, what is the probability that you will be correct? What is correct answer for: A) 20% B)…
unit0
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T student distribution

I have a population with 10000 individual, i took 10 to my samples. The values that i have inside $\bar{X}$ 70,22502193 70,26042017 70,28977621 70,2905717 70,30113496 70,32304453 70,32489699 70,3434273 70,41455295 70,46876484 $\mu$ =…
user157915
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Why doesn't Wilks 1938 proof work for misspecified models?

In a famous 1938 paper ("The large-sample distribution of the likelihood ratio for testing composite hypotheses", Annals of Mathematical Statistics, 9:60-62), Samuel Wilks derived the asymptotic distribution of $2 \times LLR$ (log likelihood ratio)…
ratsalad
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