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Hypothesis testing- with normal approximation

In Europe the diameters of women's rings have mean 18.5 mm .Researchers claim that women in Jakarta have smaller fingers than women in Europe .The researchers took a random sample of 20 women in ...
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3 views

Creating a single scale using multiple variables

Hello everyone I am new to the forum. I have a question about how to operationalize variables in survey data. So, The survey asks respondents to give their opinion on a number of issues. There are 6 ...
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5 views

Calculating annual returns of Bid using R

I want to solve the following problem using R. A chit fund has 25 members. Each month they contribute Rs 2000 each. End of the month, the person who bids the lowest for the corpus, gets his bid. The ...
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1 view

What is Importance Value?

I am reading this paper that talks about Principle Components analysis and Importance Values(IV) here Is this Importance Value a statistical concept? I could not find any information about it in ...
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1answer
12 views

How would I calculate the standard deviation of a sample given the sample size, mean, and sum of the data's squares?

For example, given: $\sum_{i=1}^n x_i^2 = 10$, $n=10$, and $mean = 10$, how would I go about calculating the standard deviation? The formula for standard deviation requires me knowing what $\sum_{i=1}^...
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5 views

How low should an ICC be to justify disaggregating (i.e. ignore clustering) a multilevel/mixed model?

It is conventional wisdom that ICCs can be used to estimate how much clustering/non-independence is occurring in data consisting of two or more levels. ICCs can inform whether a multilevel/mixed model ...
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5 views

Is it appropriate to use 3 linear regressions to assess the impact of one common independent variable?

I need to assess the impact of cultures on urban economies. The hypothesis is that more entrepreneurship oriented culture will better facilitate the local economy, controlling for other factors (that ...
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3 views

Why is the stochastic gradient of a layer almost orthogonal to its weight?

In the paper Fixup Initialization: Residual Learning Without Normalization. In Page 5 when talking about effects of multipliers, the authors mentioned that Specifically, as the stochastic gradient ...
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3 views

Finding the MAP estimate for an object's position

At an initial level I understand where MAP estimates come from. However, I'm having a problem determining how to find an optimal MAP estimate for a known prior, given data, and noisy range estimates......
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5 views

Regression training and testing error

Let’s say we fit a linear regression. What does the correlation between its training error and testing error say about the model, its performance or the data? What does a very low or very high ...
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4 views

How to calculate confidence interval and p-value for percent change of treatment relative to control?

I'm analyzing the result of an experiment where the dependent variable is a count variable (# of purchases), and the unit of observation is an individual. The way I'm calculating the treatment effect $...
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5 views

Extracting the functional form of the likelihood from the function `msm()` in R

Is there a way of extracting the functional form of the likelihood function that gets formed by the msm function in R? How can I extract the likelihood function ...
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0answers
9 views

asymptotic distributon, posterior mean

Suppose $X \sim Bin(n, \theta)$, $\theta \in [0,1]$. Considering a prior distribution for $\theta$ from $Beta(a,b)$, we get a posterior distribution $\theta|X \sim Beta(a+X, b+n-X)$ and so we get the ...
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6 views

Equivalence Testing in multivariate regression models

This questions seems to have been asked, but never answered before. The question I have is: is it possible to implement the idea of equivalence testing in multivariate regression models? For example, ...
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10 views

How the values in word2vec embedding are created for each word

I was going through word2vec materials from Andrew Ng's course and below is what i understood. -> Step1 A matrix of shape embedding_size*number_of_unique_words is created and populated with random ...
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1answer
24 views

Statistical test to verify if a population has a average of k times another

Consider the situation where there are 2 positive distributions with unknown expected values $\mu_1$ and $\mu_2$, We have samples $S_1 = \{x_1, x_2, ..., x_n\}$ and $S_2 = \{y_1, y_2, ..., y_n\}$. ...
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5 views

Comparison of MAE and Mean to illustrate the error magnitude

I have predicted a time series with positive, zero and negative values. As error measurement I used the Mean Absolute Error (MAE). In order to give the reader of my paper a better understanding ...
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0answers
15 views

which interactions to explore between sex, age, height to predict weight

As a learning exercise I'm running linear regression to predict person's weight from: sex, age, height. here's a few sample lines ...
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1answer
11 views

If x out of y choices are more likely to happen, how likely are the x choices?

If there are y choices that survey takers can pick, and generally all are equally likely, but for a certain subgroup, x of those choices are a certain percent more likely, what is the probability of ...
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8 views

Help with using Ordinary Least Square Regression [on hold]

Error in summary(model_ols) : object 'model_ols' not found
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0answers
29 views

Smooth bivariate interaction decomposition in GAM models

Background Consider the following additive model containing a smooth bivariate interaction term: $y = f(x,z) + \epsilon$ where y is a continuous outcome variable, x and z are continuous ...
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10 views

If the loglikelyhood function of $Y$ is $\log \binom {N}{Y}+Y \log p+(N-Y)\log (1-p)$ what is the meaning of “$Y$ is linear in $\log \frac {p}{1-p}$”

If the loglikelyhood function of $Y$ is $\log \binom {N}{Y}+Y \log p+(N-Y)\log (1-p)$ what is the meaning of "$Y$ is linear in $\log \frac {p}{1-p}$" The following taken from a book by W. Stroup on ...
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7 views

How can parameters be modeled differently if they share hyperparameters?

In one popular example of multilevel Bayesian models (2007 Gelman et. al paper), radon exposure in a household is modeled as a function of the county and whether the house has a basement. In this ...
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11 views

Decomposition of Mahalanobis distance: Where's my mistake?

Kim (2000) gives the formula for the decomposition of the Mahalanobis distance: $$ (\mathbf{x}-\mathbf{\mu})^{T}\mathbf{\Sigma}^{-1}(\mathbf{x}-\mathbf{\mu}) = \sum_{i = 1}^{d}(1 - \rho_{i}^{2})^{-1/...
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20 views

Prediction of $X_{n+1}$ with Yule-Walker estimate

Consider a causal AR(1) process $X_t = \phi X_{t−1} + Z_t$ with $(Z_t)$ iid with mean 0 and finite variance. I am reading in a book, that $\phi X_n$ is the best predictor for $X_{n+1}$ because it ...
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0answers
13 views

Are these two distributions independent?

In a probability cheatsheet, there's the following claim: That $Z_1$ and $Z_2$ should be independent seems very unintuitive to me. It seems to me that if $Z_1$ is high, then $Z_2$ is low, and vice-...
2
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1answer
25 views

What is the difference between Empirical and analytical PDF and CDF? More Precisely what would be the difference in their plotting?

I am relatively new to statistics with no statistical background whatsoever, I have an assignment in which i have to plot different distributions in these four manners, i have a gist of empirical PDF ...
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8 views

Beta coefficient in linear regression [on hold]

Given where estimate of b, b hat can be expressed as I know we get the above form by min sum squared of residuals: min e^2=(1-Xb)^2 But how about below form, how can we derive it where sample ...
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0answers
9 views

Kalman filter multi-step prediction

I have historical data for five correlated time series, denoted by $\{\mathbf{x}_t\}_{t=-m}^0$, where $$\mathbf{x}_t\equiv[x_{1t}, x_{2t}, x_{3t}, x_{4t}, x_{5t}]^\intercal.$$ I already have ...
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9 views

Treating Outliers [on hold]

I have to build a Logistic model to predict churn(telecom). There are large no. of outliers (>1000) in data of 66000 rows. What is the preferred method to treat the outliers? Can it be replaced with ...
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1answer
17 views

How to calculate / correct Standard Error or Confidence Intervals for bounded scales?

When conducting an experiment, often the data collected is interval or ratio, and as such unbounded. However, when attempting to make inferences about the population, reality often provides us with ...
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14 views

Effective way of visualizing break down of time durations

Forgive me, I'm not very well seasoned in statistics and its visualization but I'm a well seasoned python developer and can use the basics of pandas, matplotlib, etc... I have a dataset representing ...
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3 views

Contrasts Intutition Sum of Squares and Df

I am reading about contrasts for a class and at some point the formula for the sum of squares of a contrast is randomly stated. The author mentions then that constrasts display one degree of freedom ...
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0answers
11 views

How to handle missing values in a bootstrap resampling distribution?

I am creating a function that calculates point and interval estimates for a statistic of interest. I get the interval estimate through bootstrapping. However, it occasionally occurs that the statistic ...
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20 views

What is the intuition behind pi in the PDF of a Normal Distribution ? Is it related to some sort to a circle / sphere

The PDF of a Normal distribution is given as below I am aware of the various properties of Normal distribution and how the two parameters mu and sigma affect the shape of the distribution. What is ...
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7 views

splitting sample

first I'll try to summarize my data briefly: Each of my cases is a married couple, for which skin resistance (SR) was measured over a short period of time. Variable A contains the correlation of the ...
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0answers
12 views

Classifier output has 3 distinct peaks. Why? [on hold]

I trained a classifier on this dataset from r/ChangeMyView (https://chenhaot.com/pages/changemyview.html) on individual comments to predict whether or not that ...
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0answers
19 views

Usig sigmoid function 's' in logistics regression, how this '1' calculated in s(1.805)? [on hold]

p(+|x) = P(Y = 1|x) = s(w·x+b) = s([2.5,-5.0,-1.2,0.5,2.0,0.7]·[3,2,1,3,0,4.15]+0.1) = s(1.805) = 0.86 Usig sigmoid function 's' in logistics regression, how this '1' calculated in s(1.805)? p(-|x)...
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5 views

Multiple correspondence analysis, definition of distance between two categories of the same question

From the text : Multiple Correspondents Analysis by Brigette LeRoux The data for this quesiton is: The definition of $f_k$ is $f_k = n_k/n$ where $n$ is the total number of individuals and $n_k$ ...
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0answers
22 views

What is the probability that a man arrives at work later than on the previous day but not more than 5 minutes later.?

A man leaves his house at the same time every morning and the time taken for journey to work has the following probability density function: $f(t) = \ \left\{ \begin{array}{ll} 0 &; t<...
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0answers
5 views

What is the minimum sample size required to train a linear neural network

What is the minimum sample size required to train a linear neural network. I have 1460 sample size and i apply linear neural network on this data after necessary featuring engineering but my result is ...
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0answers
6 views

Is Kruskall-Wallis H test suitable to influence marketing plan after survey?

I've run a survey which received around 270 responses from a population of around 5,500. The survey asks brief demographic questions followed by opinion questions, akin to the following: Demog Q 1: ...
2
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2answers
64 views

Is the assumption of normality of the error term needed to use p-value?

I have been thinking lately about the following: 1. Is the normality assumption of the error term really needed in order to make use of p-values for linear regression models? A previous CV post (...
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2answers
29 views

Expected value for a function with a normal distributed random variable

I have a random variable $X \sim N(\mu, \sigma^2)$ and a function $5x^2 + 2x$. How can I calculate $E(g(x))$ ? I have two ideas, altough I'm not sure which one is right: $E(g(x) = \int_{-\infty}^{\...
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0answers
11 views

How to assign weights to data columns [on hold]

I have got two observations of this format: A: -1.9 3 3 -5 4 3.8 -2 8 5.9 B: -18.81 -18.87 -19.37 -19.24 -19.46 -19.23 -19.06 -18.93 -18.71. I want to find clusters in this data. For that purpose I ...
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0answers
12 views

Measuring spatial autocorrelation with simple pop. data

I am trying to measure the spatial autocorrelation of a matrix populated by 1s (unvaccinated), 2s (vaccinated), and 0s (unoccupied). An example of what kind of data I'm dealing with is in the image ...
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1answer
21 views

If the datapoint furthest from the y‐axis was excluded, what would happen to the associations seen?

looking at the Figure below, what would happen to the association if the datapoint furtherst from the y-axis was excluded? Current linear association indicates: Diabetes prev = -0.0171183 x BT ...
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0answers
7 views

Oversampling methods for numerical data (regression)

There are many oversampling methods for categorical labels (for example SMOTE and Rose, etc.). But, are there oversampling method for numerical labels (the thing that I want to predict with my ...
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0answers
34 views

When covariance matrix will be identical to the correlation matrix [on hold]

Under what conditions will the covariance matrix ∑ be identical to the correlation matrix, whose (i, j ) entry gives the correlation between attributes Xi and Xj ?
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1answer
11 views

Use of expression “statistically significantly predicts” based on in-sample analysis

Suppose one estimates a linear time series model $$ y_t=\beta_0+\beta_1 x_{t-1}+\varepsilon_t $$ and finds that $\hat\beta_1>0$ and the $p$-value associated with $\hat\beta_1$ is lower than the ...

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