Questions tagged [variable]

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How to model a continuous variable lying between [0,1] [duplicate]

I have a set of data in which the dependent variable Y is a continuous random variable in the interval [0,1] (i.e. it can take the value 0 and 1). This is an insurance dataset so the Y has many 0 (...
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7 views

“Compound variables” Is this the correct terminology?

I am looking for a term to describe the concept of a multi-characteristic variable. Examples of this are a) vectors - have both magnitude and direction b) Olympic records - have both event (...
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1answer
19 views

Putting into words variable transformation

If Y is a random variable which comes from a transformation of X : $ Y = \phi(X) $, the formula for the tranformation of this random variable can be written as follows : $$ F_Y(y) = P(Y \leq y) = P(X \...
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1answer
133 views

BMI Category is qualitative or quantitative

I know for sure that BMI(Body Mass Index) is a quantitative variable as it is a continuous variable. But is that BMI Category derived from the BMI a qualitative variable or a quantitative variable? (...
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1answer
47 views

Is a variable on scale 1-100 considered ratio or interval level?

Is the variable at ratio or interval level if it can take any value between 1 and 100 but not 0? I cannot determine using the definitions of ratio and interval variables.
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Different Independent Variable value to Same Dependent Variable Value model selection

I would like to run a predictive model, but my DV records are repeated with different IV scenario. Could one please told me which model should I use in this case? Like Linear Regression, Decision Tree ...
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20 views

Multivariate Regression: Both Continuous and Categorical Predictor Variables

I am involved in a meta-analysis assessing the role of multiple baseline characteristics (e.g. age, BMI, symptoms and signs) in a given disease. One element of our analysis includes a multivariate ...
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12 views

creating a continuous variable from ordinal variables

Could I simply sum up ordinal variables (some 4-,some 7-scale) to create a continuous dummy variable, and include it in a regression model? E.g. ...
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1answer
21 views

What is constant and variable error

What is constant error (CE) and variable error (VE)? I’ve seen the terms in several papers.
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44 views

How do I designate a variable in a linear model to be a covariate in R?

So I want to make this equation for example: y = mu + Strain + Insect + Strain*Insect + BW_final Of all these variables, strain and Insect are controlled variables, but BW_final is an independent ...
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1answer
13 views

How to distinguish between a variable and a control factor in Anova design

Suppose I have an experiment in which participants are presented with different types of colored objects, hence 4 variables are introduced (i.e., blue, red, white, black). Participants are then ...
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1answer
46 views

How do I interpret this dot chart? [duplicate]

I got this as a result (I can provide more information about the data itself if you would like it). I was curious about how one should interpret this chart that was created in R. I understand it has ...
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Assigning weights to features for clustering

I want to run a K means clustering algorithm (using scipy/scikit) on a 1mn records dataset. I have a list of 5 features. Each of these features have a predetermined weight assigned to them: F1, 25% F2,...
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Normalization/standardization in optimization problems

When working on optimization problem, do variables need to be standardized? Why or why not? Couldn't find too much literature on this.
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1answer
107 views

Likert scale 0-4 or 1-5

I am conducting a study with Likert scale questions and my thesis advisor advised me to rescale the answers from 1-5 (strongly agree-strongly disagree) to 0-4. She says this will help in the ...
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2answers
53 views

Multiple regression, simple regression or other?

I'm attempting to put together a research proposal where area knowledge (Western Asia) is my speciality but where the statistical methodology I need to answer my research question is not and I'm ...
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11 views

Interpretation of Coefficients if Dependent Variable are Residuals from Another Regression Model

I try to model daily stock market trading volume with a bunch of independent variables like stock returns, stock price volatility, etc. in a time-series regression model. In the first place, I ...
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1answer
22 views

Is data observed from the internet counted as primary data?

I need to find primary data (2 variable) to conduct a research about correlation. Are data that I observed from the internet (example: from youtube.com/amazon.com) counted as primary data?
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1answer
45 views

Conditional Expectation(s) of Multiple Random Variables

I am having a bit of trouble with one of the problems I am working right now. The problem is: "What is $E\left \{ E\left \{ E\left \{ Z \mid X , Y \right \} \right \} \right \}$ ?" During an ...
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1answer
25 views

Categorical variable as independent variable [closed]

I am using the variable education level as a control variable and this variable consists of 7 education levels (1-7). Now I can't use it as it is converted in the data. My teacher has messaged me that ...
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1answer
46 views

Dividing Two Random Variables

I am having trouble with a problem that I am working on for a course. I am not looking for an answer to the question (I have the answer), but I am rather looking for understanding of the concept. ...
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1answer
35 views

Standard Random Variable Notation

Perhaps this question is a bit basic for this area, so if this should go somewhere else, please let me know. I am having a bit of trouble understanding random variable notation. This is kind of ...
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1answer
18 views

Correlation with variables with small differences in sample size

I have a sample of people, around 1140 participants but not all of them answered all questions. I have to do correlation with variables , each with different sample sizes. I have 3 variables and they ...
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18 views

To determine the observation(or value) and variable in a given data

While reading "Statistics_The Art of Learning from data" book, we are given data to represent it in a histogram. I have read about the type of variables- i) Categorical variables(if observations on ...
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1answer
31 views

Can you transform the dependent continuous variable in a Logistic Regression so that Y becomes bounded between [0;1]?

I want to use a Logistic regression and my dependent variable is continuous, it is a percentage. However, the percentage is technically not bounded between [0;1]. It can take a value up to 500%. If i'...
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In a One-Way MANOVA, can one of the levels of the IV have a mean of 0 with a standard deviation of 0 on one of the dependent variables?

I realize that this sounds like a very stupid question, but I need to make sure—please stick with me. The project in question is a quantitative content analysis; for the sake of this example, let's ...
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26 views

Do percent variables need to be scaled for machine learning?

I have 101 independent variables in a logistic regression predictive model. 55 variables are continuous and 46 are categorical one-hot encoded. 5 of the 55 continuous variables are expressed as ...
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2answers
43 views

Simulating random variables from a discrete distribution II [duplicate]

I have the following discrete probability distribution where $p$, $q$ and $r$ are known constants: $P(X=0)=q$, $0<q<1$ $P(X=1)=1-p-q-r$, $0<p+q+r<1$ $P(X=2)=p$, $0<p<1$ $P(X=3)=...
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31 views

Checking Normality of Numerical and Categorical Data [duplicate]

I have come across 3 questions on the title subject. Why is it necessary to do a normality test? To check if data is imbalanced or not? Are these 4 methods of checking if the data follows normal ...
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26 views

RANDOM VARIABLE X and variable x

Does anyone understand why we commonly use x to denote variables, yet we use X to denote random variables? Personally, I find it difficult sometimes to differentiate between the two considering that ...
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30 views

Interpreting hazard ratio in Cox regression after manipulating continuous variable

In Cox regression I realize when interpreting hazard ratios (HR) for a continuous variable, it is HR per 1 unit increase. Traditionally I see this for something like per kg, per g, etc. But if the ...
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Can Omitted variable even reach the population parameter?

I have this question as an exercise question on my textbook, there is no answer though. I am wondering if D is the correct one?
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How to factor in Effect of on going Covid-19 situation in sales volume prediction model?

I have a regression model (log-log) which predicts the volume in the presence of variables like price and other promotion causals. Now given the current situation how do we factor in the effect of ...
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1answer
61 views

How many variables can be included in one multiple regression model?

I was wondering if there is any limitation regrading the number of independent variables if I want to simultaneously include all variables in one regression model.
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1answer
66 views

CDF of Z = max ( 0, X-M )

I'm trying to understand how the cumulative distribution function of a Random Variable which is a maximum function can be obtained. If $Z = \max(0,X-m)$ where $X$ is another Random variable ( Claim ...
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independent variable with two levels having one level tested two times (other level sandwiched between) for each individual in R using lme

I am trying to run lme (nlme package) analysis on a dataset where each individual (insect) is tested against two gas levels(Air, hypoxia) over time. Dataset Dependent variable cycle Independent ...
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1answer
34 views

PCA clustering and creating a new covariate for RNAseq

I am currently doing an RNAseq experiment and some quality control on data. I noticed that there seems to be some kind of batch effect that I cannot explain from the variables I already have. I've ...
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30 views

How to tell apart from variable types?

I'm not sure if this is the right place to ask this question but I'm trying to find out the following: Which variables are categorical? Nominal? What level of measurement is "prop_dmg"? What level ...
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25 views

How to code a predictor in regression when some values are purposefully unknown

I ran a psychological experiment involving two conditions. An independent variable - made up of numeric values - was present in one condition but not in the other. Accordingly, in one condition the ...
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30 views

Random Forests Variable Importance feature addition

I would like to know if the following is a valid method in concern to the final feature importance calculation: I have a number of training data with a total of e.g. 5 original features (OF). I ...
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2answers
145 views

Clarification of the stepwise regression analysis : Bidirectional elimination

I am working on a large dataset (2000 patients, 100 variable) My purpose is to identify the influence of the variable (VarX1, VarX2, VarX3,…..) on a dichotomial outcome (VarY). My purpose is to ...
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Correlated Random variables

On Matlab I would like to simulate a wireless mobile phone cell, in particular I want to reproduce the effect of shadow fading on the link between two users. So if I consider a certain 2D map, with ...
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25 views

Variable Importance sorting by absolute value of x or fully standardized coefficient?

I am looking at the output of a linear regression model and would like to sort the IVs by feature importance. In this case I want to use the absolute value of the standardized coefficients since my ...
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1answer
78 views

Convergence of random variables problem

I am trying to solve the problem from MIT Open Coursware "Statistics for Applications" problem set. Specifically the first one: "For $n \in N^*$, let $X_n$ be a random variable such that $P[X_n = \...
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1answer
16 views

Dichotomous independent variables and interpretation of regression output

I am running a regression on stata concerning the association of smoking intervention types upon participant age of first use. The dependent (age) is a discrete variable by age in years, while the ...
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1answer
59 views

Differences between realization of the random variable and deterministic variable?

The first question is that can we classify variable into random variable and deterministic variable? The second question is that The possible values taken by a random variable"X"(Uppercase) are termed ...
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29 views

Relationship of two variables over multiple time points

I am very inexperienced with statistics, so any help is appreciated! I would also greatly appreciate any recommended reading as well. We have a cohort of 10 subjects, whom we have looked at two ...
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10 views

Accounting for Inter-Sample Collection Time Variability

I'm trying to run regression analysis on a dataset that features a pair of continuous variables that are collected at a certain time (in days). Whilst the data should be collected at a specific time, ...
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27 views

Choosing variables in multiple linear regression [duplicate]

I am trying to make multiple linear regression models for multiple crops where my dependent variable is Yield of crops for ex. Yield of Wheat, Rice, etc. I have data set in which each row represent a ...
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1answer
93 views

Relationship between the variable on X-axis with the one on Y-axis

I have two graphs here and I would like to know if there is a relationship between the variable on X-axis with the one on Y-axis of each of the graphs.