Questions tagged [mathematical-statistics]

Mathematical theory of statistics, concerned with formal definitions and general results.

7,286 questions
Filter by
Sorted by
Tagged with
16 views

Your colleagues in a comp-bio lab have sequenced DNA from a large population in order to understand how a gene [closed]

Your colleagues in a comp-bio lab have sequenced DNA from a large population in order to understand how a gene (G) influences two particular traits (T1 and T2). They find that P(G) = 0.6, P(T1|G) = 0....
• 99
28 views

Is it better to have more degrees of freedom or less?

The concept of degrees of freedom appears in many places in statistics. Yet I still don't understand what is the role of degrees of freedom. Why can we just use sample size (and we need to decrease it ...
• 3,689
1 vote
11 views

• 227
1 vote
14 views

Does the number of samples, as opposed to the sample size in each sample, matter for the Central Limit Theorem? [closed]

(1)So here is a formula that describes CLT I found at https://en.wikipedia.org/wiki/Central_limit_theorem. According to the first part of the explanation, n as in Xn describes the number of samples(i....
• 11
72 views

• 139
1 vote
104 views

Can we apply hypothesis testing to not-actively sampled groups?

For argument's sake, in the below please assume that the hypothesis test we'd be considering would be a simple z-test to check whether an observed difference between two groups' means or proportions ...
• 11
1 vote
39 views

Estimation vs Prediction Vs Forecast

I already read the q/a's from here and here. These answers are quite a bit complicated for me. I need something easy to understand and explain to any interviewer. I read lots of articles like; What is ...
• 635
28 views

Average Sample Size For Curtailed Double Sampling Plan

I am currently implementing double sampling. The goal is to accept or reject a lot by only sampling a few instances from it. In a two-stage testing procedure (double sampling) one first draws a ...
• 103
29 views

mathematical model of well variability

I would like some help in how I can analyse or approach an experiment in a statistically/mathematically way. I have two plates where I applied a different technique that kills cells. I would like to ...
• 111
1 vote
15 views

Combined Probability of 5 Events with Different Probabilities and 25 Trials

I have 5 events, A through E, with individual probabilities: P(A) = 0.12 P(B) = 0.05 P(C) = 0.11 P(D) = 0.12 P(E) = 0.60 After 25 trials here were the results: A = 1 success B = 3 successes C = 4 ...
• 11
23 views

Reason behind Pareto principle [closed]

Can some one explain the scientific reason behind Pareto principle/Matthew principle.
• 101
8 views

How to correctly compare 2 correlation values using the Fisher r-to-z transform?

In https://www.statisticshowto.com/fisher-z/, it is stated that “But it’s probably most commonly be used to test the significance of the difference between two correlation coefficients, r1 and r2 from ...
• 90
1 vote
36 views

Ratio of first two moments of sample covariance eigenvalues

Suppose we form $X$ by stacking $b$ examples drawn from some distribution in $n$ dimensions as rows and look at $\{\lambda_i\}$, the eigenvalues of $\Sigma=X^TX$. Consider the following random ...
• 5,403
5 views

Multi entry raffle one win per person [duplicate]

I have a statistical question. I wanted to know the probability of winning a multi entry raffle with 20 wins and only 1 win per person. Each Person can have multiple tickets. Let’s assume I have 2 ...
14 views

Statistical test to use to compare subgroups with each other

I don't have a stats background, so I apologize in advance if my question is dummy. I sent a quiz to several people and I would like to run some statistics' tests on it (I'm using R). Essentialy I ...
27 views

• 503
17 views

Is the Karlin-Rubin theorem test the same as a one-sided monotone likelihood-ratio test?

Is the test described in the Karlin-Rubin theorem test the same as a one-sided monotone likelihood-ratio test?
• 503
22 views

Why can't the random-varibale $Q_{k-1}$ be computed once we observed $X_1,...,X_k$? and why its distribution becomes $\chi^2_{k-3}$?

We encounter hypotheses $H_{0}$ in which the multinomial probabilities $p_{1}, p_{2}, \ldots, p_{k}$ are not completely specified by the hypothesis $H_{0}$. That is, under $H_{0}$, these probabilities ...
• 503
1 vote
49 views

Are there any (exponential) families without a minimal sufficient statistic?

Bahadur's theorem says that if a minimal sufficient statistic exists, then a complete sufficient statistic is also minimal sufficient. Are there any (homogenous, identifiable) families with a complete ...
23 views

Is it OK to re-sample the same patients at multiple points in time and then use the data for classification?

I'm trying to predict which patients will have a bad outcome (BO) within the next 2 weeks based on medical readings (plus some behavioral data) from the last 6 weeks. Total data timespan is 8 weeks, i....
23 views

computing the "mix effect" in the evolution of a variable on R

Background: I am currently working on a dataset representing the evolution of the income of a hospital which hosts several medical specialties. The ratio income/medical act increases between year $N$ ...
12 views

VECM and ECM relationship?

I know that VECM can be decomposed into single equations. In my VECM with 4 variables, there are only one cointegration relationship. Then if I decompose VECM into single equations, only one equation ...
29 views

Minimize cost given working days/hours/required hours per job/start & end dates

I am trying to solve an optimization problem on Excel or Python. My constraints are the available number of employees (=20), the number of working days/month (=20), the number of working hours/day (=8)...
1 vote
24 views

Proper way to write a regression equation with multiple interaction terms

As I am about to submit my master thesis, I am having doubts about the mathematical correctness of the regression equation I have used to represent my model. A bit of context: I am predicting review ...
• 11
8 views

How to propagate errors in Model Building?

I have developed two maps using a predictive linear regression where each pixel represents a predicted value of biomass or volume. Next I want to use those predicted values of biomass or volume to ...
1 vote
43 views

Confidence interval for C-index

After asking this question earlier today, I figured the approach I should use is not very clear to me so I turn to the community hoping for some answer or good reading material because I kind of get ...
• 11
11 views

estimating variance components of random effects model without fitting the model

I have the following scenario: we are interested in the modelling a response $y_{ij} = u_i + \beta x_{ij} + \epsilon_{ij}$, where $u_i \sim N(0,\sigma^2_u)$ is a random intercept, and \$\epsilon_{ij} \...
• 1,055
15 views

Control differences with dunnett adjustment chart [closed]

Why the answer is A? but store A is not appear in the chart
18 views

How to calculate the accuracy and error rate in confusion matrix?

(0 - negative outcome, 1 - positive outcome) Am I correct? Because I found a different answer. My answer: Accuracy rate: TP+TN/ALL(58+25/58+44+23+25)=83/150 Error rate: FN+FP(23+44)= 67/150 Someone ...