A routine question from a textbook, course, or test used for a class or self-study. This community's policy is to "provide helpful hints" for self-study questions.

learn more… | top users | synonyms (1)

0
votes
0answers
15 views

Convergence in Probability to a Constant [on hold]

Let $X_{1}...X_{n}$ be a sequence of random variables that converges in probability to a constant a. Assume that $\mathbb{P}(X_i > 0 ) = 1$ for all $i$. Verify that $Y_{i}=\sqrt X_i$ and $Y_{i}^{'} ...
0
votes
0answers
27 views

Is my work acceptable? (Fitting a normal distribution) [on hold]

Sorry for the long text. But please note that what I'm asking for is not a word by word correction, but I'm asking you to do a quick skim (or two) on my method of working, and I hope to get some ...
1
vote
0answers
11 views

Simple linear regression variance of slope parameter using aggregated data

I have 200 data points, 20 subjects in each of 10 cities. The X value is the individuals income and the Y is the amount spent. I am assuming a linear relationship between income and spending with ...
0
votes
2answers
51 views

Moments of linear combinations of normally distributed variables

So I have this problem I have to solve for my homework for my Linear Regression Class that is due tomorrow and I honestly dont know where to start with this problem. "Suppose to have $X\sim N(0,1)$ ...
0
votes
0answers
12 views

Basic hypothesis testing question: how to find the c.r. for a variance test?

Let's suppose that we have two normal distributions, and a sample is taken from each (of sizes $n_X$ and $n_Y$ respectively). $X \rightarrow N(\mu_X, \sigma_X ^2), Y \rightarrow N(\mu_Y, \sigma_Y ...
0
votes
0answers
15 views

Adjusting standard deviation for 90% acceptance in normal distribution

A Company produces pins. Average length, μ = 1.008 Standard deviation, σ = 0.0045 Sample size, n= 50 Sample is bought by customer only if it is within interval 0.99 to 1.01 inch. If only ...
1
vote
2answers
49 views

What do you call this type of analysis?

I do a lot of statistical analysis at my job but I'm unsure of the terminology for what I do. I work for a lab where we screen every newborn in the state for 29 genetic disorders. That's 100,000 ...
-1
votes
0answers
19 views

State the distribution of the time he has to wait for four customers to arrive. Sketch its density and calculate mean and variance of the waiting time [on hold]

Lim operates a long-distance taxi service from the central bus terminal in Kuala Lumpur to Seremban, a town 60 km away. Customers arrive at his taxi stand at an average rate of one every four minutes ...
1
vote
1answer
23 views

Expected value and variance for the changed range

I have a distribution with E[X]=-8 and Var[X]=60 and the range of the data [-256,255]. I want to convert this distribution of range [0,256] taking the absolute value of data set. What will be the ...
3
votes
1answer
37 views

Is my work correct (easy problem, confidence intervals)

The r.v. $X$ represents the time taken by a computer in company $1$ in order to perform a certain job, and $Y$ represents the same thing but for company $2$. A sample of $n_X = 12$ computers are taken ...
1
vote
1answer
30 views

HOMEWORK: Proving Log-Series Distribution

This is just a quick query to confirm that I have this right and that my way of constructing it is correct. We were asked to prove: $a=\frac{-1}{log(1-\theta)}$ for $p(x)=a\frac{\theta^x}{x}$ for ...
2
votes
1answer
29 views

confidence interval and pivotal functions

I am struggling with this question; I am given some function: $f(x;θ) = \dfrac{2(θ−x)}{θ^2}$, if $0< x<θ$, $0$ otherwise The upper limit of a $(1 − α) × 100%$ lower confidence interval for ...
0
votes
0answers
14 views

Can I use the quadratic formula to calculate the cells of a 2 X 2 contingency table?

This is an extra credit problem in a biostatistics course. I am not looking for the answer, just a starting point... If you are given the following: The total sample size: (N = 200) The overall ...
0
votes
0answers
10 views

Need help with finding the state space / transition diagram of a markov chain

I need to find the limiting distribution for this however to do that I need to first find its transition diagram and I'm just stuck on thinking about how this M.C works. I'm not even sure on the ...
-1
votes
0answers
13 views

Recurrence or transience of countable state space markov chain [on hold]

Consider a discrete time Markov Chain with countable state space S={...,-1,0,1,...} and transition probabilities $p_{i,i+1}= p_{i,i-1},i \in$ S. Show that chain is recurrent if p=1/2 and transient if ...
0
votes
1answer
65 views

What are the key steps in solving Machine Learning Problem [on hold]

I am trying to make a summary to myself, what are the key steps for solving a Machine Learning problem. I tried to read good books, talked with peer, discussed many issues here, checked many web based ...
0
votes
0answers
7 views

How ksvd algorithm is considered generalized kmean?

I am trying to understand more details of this paper "KSVD: An Algorithm for Designing Overcomplete Dictionaries for Sparse Representation" proposed a new algorithm called Ksvd and claims it's a ...
0
votes
1answer
19 views

Tukey's Test or LSD Fisher

I'm trying to solve the above exercise, but my question begins with which test should I choose: Tukey test or Fisher's LSD? I read several things and still can not tell the difference between the ...
0
votes
1answer
25 views

Posterior predictive distribution - naive bayes

I am self-studying and trying to understand the derivation of the posterior predictive distribution of a naieve bayes model from a graph perspective. In an online course - the derivation of the ...
0
votes
0answers
16 views

Specifying SARIMA model parameters

In SARIMA model described by the equation $x_t=(1-L)^2y_t$, what are the $d, D$ and $s$ parameters? Is it $d=0$, $D=2$, $s=1$, or $d=2$, $D=0$ and then what can be the $s$?
1
vote
0answers
48 views

Hypothesis testing – abusing notation or am I missing something?

In a number of statistics books and references you can find formulas such as: $P\,(result~|~H_0)$ (Bortz, p. 114) $P\,(reject~H_0\;|\;H_0~valid)$ (Wikipedia - Statistical hypothesis testing) and ...
1
vote
0answers
7 views

How to calculate first three orders of PACF function given ARMA model?

Is there a way to calculate the first three orders (i.e. $\phi_{11}$ $\phi_{22}$, and $\phi_{33}$) of PACF given the estimated form of ARMA model, for example: ...
1
vote
0answers
14 views

Dunnett's test help

Suppose that 30 percent cotton content is a control.Use Dunnett's test with $\alpha=0.05$ to compare all the other means with control. I'm using Montgomery book for study, then sorry if the ...
5
votes
3answers
108 views

Monty Hall (goat) problem w. elementary events

I am trying to solve the Monty Hall problem with elementary events, but I just can't seem to get it right: I define four sets: Actual door ($R$) User's first selected door ($S$) Moderator pick ...
1
vote
0answers
13 views

DCCA clustering algorithm understanding

I try to understand the step 2.5 of the DCCA clustering algorithm pasted below. The original reference is here and the PowerPoint presentation is here. I have the following questions: Do we perform ...
0
votes
0answers
59 views

Statistics Test Question - Help needed! [closed]

I am really terrible at statistics and basically don't even know where to begin on answering these. Any help would be appreciated. I've googled but there is some much info that it confuses me and I ...
2
votes
0answers
23 views

Allocation of design points in an experiment

I would like some hints with the following problem. Thanks for any help in advance. An experimenter wants to design an experiment for estimating the rate of change in a dependent variable Y as an ...
2
votes
1answer
24 views

How to compare two reviews, when one has more participants than the other

Hi I only did some basic stats at school but now I need to rank some data for a project, and I've run into this kind of scenario Game A: 1000 Reviews, 900 Positive and 100 Negative, so 90% positive. ...
0
votes
1answer
56 views

Conditional probability: how do i find the conditional probability given two parameters?

It is known that 25% of full time workers are also students. It is also known that 64% of the population work full-time and that 22% of the population are students. If a member of the population is ...
0
votes
1answer
31 views

How to introduce the error bars in text?

I want explictly to state in my written text that the error bars in the current plot and all of the following ones represent the 95% percent of the calculated mean. However, the metric changes in the ...
0
votes
1answer
22 views

Two-step Engle and Granger's procedure

If I want to check if there is cointegration between $X_t$ and $Y_t$ in the following model, is it enough to check p-value of Breusch-Godfrey test? The maintained hypothesis in this test is no ...
0
votes
0answers
22 views

Specifying integration level of time series

How to specify the level of integration of $X_t$ in such case? I am familiar with testing integration in R, cointegration strategies, but which method to use in such case? In brackets there are ...
2
votes
1answer
35 views

Can we estimate a missing Y value from a three factor experiment?

In preparation for an examination I'm looking at some old questions, and I could use a little help with figuring out what to do here: In a three-factor experiment the researchers lost the results ...
0
votes
1answer
35 views

Generate random number with normal distribution?

I encountered this question, where given it is a normal distribution, how do we go about it to generate a series of random numbers beside Monte Carlo? The clue given was using exponential function.
0
votes
0answers
38 views

Likelihood ratio test for two independent poisson distributions

Suppose that $X_1, X_2, ..., X_n \sim Pois(\mu)$ and $Y_1, Y_2, ..., Y_n \sim Pois(\theta)$. $X$ and $Y$ are independent. Derive the likelihood ratio test of $H_0: \theta = \mu$ versus $H_a: \theta ...
1
vote
1answer
35 views

Projection Matrix Help

I'm having trouble understanding the following in a review textbook I'm using, particularly the long equality with inverses and transposes, and the subsequent conclusion regarding the rank and trace ...
2
votes
1answer
33 views

Standard Deviation of a sum of identical random variables

In a variation of the famous "how many chips are in a bag of Chips Ahoy" inference investigation, I am asked to make a confidence interval for the number of chips in 50 cookies (the amount in a bag) ...
1
vote
1answer
30 views

Probability homework question with specifity, sensitivity and prevalence

Assume that a diagnostic test for EPM (equine protozoal myoeloencephalitis) has a sensitivity of 89% and a specifity of 92%. The prevalence of the disease is 1% What is the probability that ...
1
vote
0answers
17 views

Restricted Maximum Likelihood Estimation for Linear Mixed Model

The maximum likelihood estimation procedure for linear mixed model is described in this link. It seems to me that something is wrong there. In their Restricted Maximum Likelihood section the first ...
2
votes
1answer
21 views

G-Means: Learning K in K Means

I am currently trying to understand the paper 'Learning K in K-Means' by Hamerly & Elkan (2004), which is the paper implementing G-Means, an automated way in selecting K for K-Means. There is one ...
0
votes
1answer
41 views

Why is multiple regression to be preferred over simple linear regression? [closed]

How does a multiple regression differ from a simple linear regression and why is the use of a multiple regression generally preferred over a simple linear regression?
1
vote
3answers
49 views

Learning material for regression analysis

I found a lecture notes from regression analysis but it was quite hard to learn from it. Those notes were aimed for students who had read just basics of statistics beforehand. I have a background in ...
0
votes
1answer
30 views

mean and standard deviation from rnorm(5, mean = 0, sd = 1)

I am trying to figure out a good way to find mean and standard deviation from sampling rnorm(5, mean = 0, sd = 1) 1,000 times. I thought about using a for loop and combining the result of rnorm as a ...
0
votes
1answer
24 views

Chi Square Statistic - Which variable should be defined as the dependent variable?

I am stuck with this very basic question which I need to answer using SPSS for the problem set pasted in cursive below. Any pointers in the right direction would be very much appreciated. Thank you. ...
0
votes
1answer
20 views

Addition Rule and Conditional Probabilities

My question comes from part of an assignment question that I am having difficulty understanding. I have a community of people, males and females split into three age categories (A, B, and C), so ...
0
votes
0answers
14 views

Some difference in notation in a project report

I am focusing on a specific model in my study. When I am writing my project paper, for describing the estimation procedure, can I describe it more generally with some difference in notation than my ...
0
votes
0answers
7 views

MLP with hidden layer units more than input layer

What is an acceptable scenario in multi-layer perceptron when the number of neurons in the hidden layer is more than input layer neurons. What changes to the cost function should be made for such a ...
0
votes
0answers
37 views

Restricted Maximum Likelihood Estimates of Multilevel Regression Model

A two-level regression model : $$Y_{ij} = \gamma_{00} + \gamma_{10}X_{ij} + \gamma_{01}Z_j + \gamma_{11}X_{ij}Z_j + u_{0j} + u_{1j}X_{ij} + e_{ij}$$ where $e_{ij}\sim N(0,\sigma^2_e)$ and , $$ ...
3
votes
2answers
60 views

How does the proportion of X > a compare to the proportion of Y > a?

I am completing CS109 Data Science class available online for free. I'm not quite sure what they are asking for. In general, if group A has larger values than group B on average, does this ...
0
votes
0answers
11 views

What is negative reconstruction error for Deep Belief Network?

I was studying Deep Belief Networks and started testing a small example. For the sake of these question consider the one at deeplearning tutorials Observation 1: I noticed that my reconstruction ...