Mathematics Stack Exchange
Mathematics Stack Exchange

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.

37109 questions
1
vote
0 answers

Asymptotic econometrics and central limit theorem

I have a probably stupid question, but it's a real mix-up in my head. When we do econometric analysis for large datasets we say normality of the residuals is not necessary because of the central limit theorem and t-test converges to a standard…
Alex
  • 11
1
vote
3 answers

PMF function: joint pmf question

For the PMF of $X$ $$P(X = x) = (0.5)^x \;\text{ for }\;x\in\mathbb{Z}^+,$$ would the PMF of $Y= X-1$ just be $$P(Y = x) = (0.5)^{x-1}.$$
12343242348923042
  • 11
1
vote
0 answers

What is the purpose of working on a logit scale in Partial Dependence Plots?

What is the purpose of working on a logit scale in Partial Dependence Plots? (binary classification) One could simply go about as follows: Grow a forest Suppose x has v distinct values in the training data set. Construct v data sets as follows. For…
user1134616
  • 111
1
vote
0 answers

TI Calculator issue in computing sample distribution

I've noticed my TI-calculator has been given me these strange answers. I'm sure I did the problem right: "Biologists are studying a starfish population. The mean starfish length is 18 cm with a standard deviation of 7 cm. If a sample of 49…
user111019
  • 151
1
vote
1 answer

Probabilistic Model

can you help me with this problem of statistics? " Consider the experiment of extraction of $3$ balls from an urn containing 16 red balls, $19$ yellow and $5$ blue. 1) Compute the probability of extracting zero red balls, in the event that…
Blackie
  • 13
1
vote
4 answers

$E(X)= a$ for some constant $a$

Let $X$ be a random variable and let $a$ be a constant such that $f_X(a-y) = f_X(a+y)$ for all $y$. Prove then that $E(X) = a$. the hint Iam given is to show that $E(X) - a = \int_{-\infty}^{\infty+} (x-a)f_X(x)dx = 0$ but i still don't know how…
Danny
  • 1,547
1
vote
1 answer

Confidence interval on the difference of probabilities

Suppose you have two coins 1 and 2 with unknown probabilities $p_1$ and $p_2$ of coming up heads. You then flip coin 1 $n_1$ times and coin 2 $n_2$ times. I would like to then be able to say that with a 90% confidence $p_2 -p_1$ is between some…
user123663
  • 11
1
vote
0 answers

PLS discriminant analysis - explained variance

I have a problem understanding a main thing about the PLS discriminant analysis. In my program there is an output, where the amount of variance explained by each factor for both the independent and the dependent variables is printed out seperately…
user123625
  • 11
1
vote
2 answers

Two uncorrleted variables have some relationship?

Can two uncorrelated variables have some relationship? If so, could you give me some examples?
afsdf dfsaf
  • 1,687
1
vote
1 answer

Statistics question on approximating binomial distributions

I keep on getting different answers for this problem. Can someone help? A fair coin is tossed 100 times. What is the probability that more than half of them are heads? $ P(X \geq 51) = 1 - P(X < 51) = 1 - binomcdf(100, 0.50, 50) = 0.460$ But when I…
Guest
  • 167
1
vote
1 answer

Online Voting Theory Resources?

I'm trying to learn about voting theory, but so far I have had a spotty education on the topic through random googling. Can anyone recommend a website or book so I can learn more about it?
jd123
  • 349
  • 3
  • 11
1
vote
0 answers

Robustly finding discontinuities in piecewise fitting

I'm attempting to implement a piecewise harmonic curve fit, and while I'm able to fit arbitrary curves quite well, I'm not sure how to robustly select a point to break at. With my very clean synthetic data, it seems "obvious" that I can break at…
Nick T
  • 1,763
1
vote
1 answer

Z table in statistics

Question involves converting 4 and 15 to Z table with given standard deviation and average. But now, they ask for percentage of probability of anything less than 4 or greater than 15. What am I looking for here on the Z table?
vanessa
  • 11
1
vote
0 answers

Combining points with win percentage to get an efficient rating

We have a FIFA league set up between a few friends of mine. It's a fun way to keep track of the scores and who is the best player, however we have a little problem with the rankings. At the moment, it is done on points. However this is unfair as it…
Kaish
  • 6,126
1
vote
2 answers

How do I tell if a sample data is roughly normal? (Normal Probability Plots)

I don't understand why this graph shows that the data set is roughly normal: I can see that the points are evenly spread out below and above the line, but why does that make the data approximately normal? I'm also having trouble understanding…
Guest
  • 167
1 2 3
…
99 100