A random variable $X$ is called continuous if its set of possible values is uncountable, and the chance that it takes any particular value is zero ($\text{P}(X = x) = 0$ for every real number $x$). A random variable is continuous if and only if its cumulative probability distribution function is a ...

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Comparing Peptide Amino Acid Composition: 2 Independent groups, Non-normal data, discrete data

I have two large groups of peptides, "positive" group (n = 368) and "negative" group (n = 880). The average length of the peptides (in each group) is about 20 amino acids. What I am trying to do is ...
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55 views

Unified Variable Classification

I am trying to go beyond Stevens' Level of Measurement Typology. Here is what I have so far: Discrete Variables Nominal (like Apple, Banana) Ordinal (like 1, 2, 3) Count (like 0, 1, 2) ...
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33 views

How should one call a variable which values can be summed? [duplicate]

Some continuous variables like Precipitation have values that can be summed. But others like Temperature do not. Adding two temperatures together simply does not make sense. Do these variables whose ...
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1answer
15 views

How to interpret simple effect of a variable interacted with several others?

I am sure this has been asked before (similar here but no answer). But I have not found an answer yet. To give you a short frame: I am researching firm level data and I am ivestigating several ...
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1answer
60 views

Does it make sense to interact two continuous variables in econometrics?

Let's say I have three variables: Variable A, B and C, where C is the product of A and B. Both A and B are continuous variables. If I regress Y onto A and B, A is significant and B is not. Then, if ...
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16 views

Testing the utility of adding a continuous variable to a nonlinear regression.

Let’s say I have the hypothesis that soil fertility affects the relationship between weed biomass and crop biomass. One way to go about testing that hypothesis might be to model the relationship ...
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17 views

Interpreting GLMM output in SPSS

In SPSS I carried out a linear mixed models analysis by going to Analyse - Mixed models - Generalized Linear... I know how to interpret my categorical data output (I hope) - one of the categories is ...
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38 views

How to normalize mixed continuous/discrete features for DNN?

I have had some success training my deep neural network (with ReLU hidden units) by first normalizing the features of my data set to zero-mean-unit-variance. Each sample of my data set has 600+ ...
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52 views

What statistical test should I use if the relationship between two variables is neither linear nor monotonic?

I am confused. My scatterplot says that the relationship between the two variables is not linear, so I can't use Pearson's correlation and neither is it monotonic, so I can't use Spearman's ...
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21 views

What are the different ways to discretize continuous features?

I'm working on classification problem. I have a set of continuous & discrete features and I'm trying to list my features in their order of significance. Using chi-squared test as a filter & ...
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15 views

Interaction with Continuous Variable and Between Subjects Variable

I am trying to test the interaction between three factors: One is a within subjects factor ("Scene Component": memory scores for difference scene component types: objects vs. backgrounds) One is a ...
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22 views

Why big difference between categorical and continous variable inregression analysis?

I am currently doing a survival analysis where I want to adjust for several confounders. One of my variables, which I will name MyScore is a score from 1-5. When I enter MyScore as a continuous ...
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44 views

How to write down a logistic regression formula for continuous and categorical variables?

I have a logistic regression with five explanatory variables (x) and Y is binary. I will present a small work tomorrow on a powerpoint and wondering what the neatest way is to write my logistic ...
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37 views

Categorizing a continuous predictor?

If you had to split a continuous (independent) variable ranging from 0 to 9 and reflecting the number of x (e.g. number of cigarettes smoked), would you rather do: Median split (but then also ...
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1answer
36 views

Plotting 2 fixed factors and continuous covariates

I measured the reflected radiation: the independent variables are the incoming radiation (continuous), the treatment (Control-Encroached; fixed) and the height (1-3; fixed). I want to plot these in ...
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1answer
25 views

Best method for predicting a numeric response from multiple proportional predictors?

I have some data where I want to predict a continuous, approximately normally distributed response/dependent variable with three predictors which are all proportions (i.e. 0-1). The three proportions ...
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0answers
28 views

How to test when the data is both binary and continuous?

I gave a recall test to the participants to examine the accuracy of their answers. I have one IV with two levels, present or absent. I have 11 DVs (questions in the exam), 4 of which are continuous ...
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1answer
31 views

1 continuous predictor and a 3 level ordinal outcome

I´m evaluating the impacts of logging in a forest, so my independent variable is the intensity of logging (i.e. trees per area) and my dependent variables are the injuries in the residual trees (the ...
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27 views

scale & why normality does not matter

So I was looking at the world happiness report 2013. In most of their questions they used "0 to 10 end-labelled scale". So ya, basically "0, 1, 2,.., 9, 10". I understand that these kind of scale data ...
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31 views

Relationship between expectation and probability with continuous variables

I've tried to word this question to the best of my ability but I may have got some of the terminology wrong. Example: I have a machine producing various lengths of knotted string. If I have a string ...
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2answers
74 views

ANCOVA intercepts - does R center data?

I have 2 fixed effects and 2 continuous predictors. Nothing interacts so I believe I want a model of the form: $$Y_{ij} = \mu + \tau_i + \beta_j + \gamma_1(X_{1ij}-\bar{X_1}) + ...
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2answers
62 views

How is $p_{i}$ for a set of continuous data points related to the probability function $f(x)$?

I have the following set of continuous measurements: 155.08 178 264.81 238 378 140.38 130.5 140.69 155.5 To average this data, I sum the values and divide by the ...
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1answer
46 views

What methods exist to compare data sets from two different types of distributions

I want to compare two different types of data sets how well they correlate with each other. Lets say I have two datasets one follows a continuous distribution and another follows a poisson ...
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1answer
60 views

Normalizing a Continuous Variable for Appropriate Use Alongside Binary Variables

I am fitting a model where I estimate my Dependent Variable based on about 20 Binary Variables (0/1), and one continuous variable. I've read about the importance of normalizing that continuous ...
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1answer
30 views

Using counts of a continuous random variable to establish an unknown probability density function

The precision of a given measuring device defines a window over the probability density function of whatever is being measured. For instance, if a measuring tape is precise to 0.1 inches, then the ...
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repeat measures, continuous/scale data, 3 dependent variables, 7 independent

Children played a comprehension game on an iPad and their attentional patterns were observed and coded for using video coding software. The duration of 7 different behaviors were coded for. Pupils ...
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1answer
20 views

Is there ever any reason to discretise continuous ground truth if doing classification?

Is there a case where discretising continuous response improves classification performance? For example: A response variable is in the range 0 to 99. There are 10 classes defined by the following ...
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1answer
53 views

Model to predict categorical outcome from continuous and categorical variables

I have to fit a model to test whether Learning (1=learned, 0=failed) depends on lizard sex (M or F), Lizard SVL (snout-vent length), or an interaction of the two. I am new to both R and this website. ...
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19 views

Make up a new continuous variable from other two

Suppose you are analyzing gambling addiction behavior (I changed the actual subject to make it more understandable) and that you consider the following interpretation: A really good player is one ...
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1answer
42 views

ANCOVA or not? Non continuous covariate

I have done an experiment with an independent and dependent variable. I repeated the experiment 5 times. Obviously all the repeats will be different from one another, some of them significantly so. ...
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36 views

hurdle models using continuous data and covariates

I was wondering if I get some advice about fitting hurdle models using continuous data and covariates. I have some continuous data that are generally well fit using a right-skewed distribution such as ...
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19 views

How do I handle continuous variables that depends on a another discrete variable?

I am trying to create a classification model with independent variables IV1, IV2 and IV3 and dependent variable DV (DV ~ IV1 + IV2 + IV3). Now the problem that I am facing is that IV2 exists only ...
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1answer
27 views

Multivariate Linear Regression with continuous and discrete explanatory variable

I have some trouble to apply a multivariate linear regression on my data. I have two features gross_area which is continuous, nb_bathrooms which is discrete (1,2,3) and a dependent variable y which is ...
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1answer
62 views

Transforming continuous variable to ordinal for estimation with ordered logit

I currently have a continuous variable. However, I would like to transform it into 5 intervals using cutpoints of my choosing to carry out an ordered logit estimation. That is: Will this affect ...
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2answers
64 views

Is recoding a categorical variable into a continuous variable possible?

I'm trying to see if it's possible to recode a categorical variable into a continuous variable. The data would probably not permit it but what if I really needed to find the mean and SD? Is there ...
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1answer
103 views

Why Binning Variables in Predictive Analytics?

Lot of discussion in CrossValidated focuses on optimal binning methods, binning example etc. But I am trying to figure out what are the scenarios that I have to bin variables whereas it's better idea ...
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2answers
91 views

Large differences between raw (plotted) data and least-squares means from mixed model

I’m analysing data with mixed-models (using the afex package which I believe is based on lme4) from an experiment that had a ...
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1answer
55 views

Marginal Probability Density Function of Joint Distribution

I have this question regarding marginal probability density function of joint distribution. Following is the equation I have. $$f(x,y) = \begin{cases} \frac{3}{2} y^2 & 0 \le x \le 2 \text{ and } ...
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1answer
191 views

Correct glmer distribution family and link for a continuous zero-inflated data set

Data set details: Zeros are "real" (volume) Data set is heavily left skewed (even when zeros are excluded) Response is continuous (volume) Can anyone recommend a distribution family and link that I ...
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1answer
37 views

Regression models in temperature data

I am quite new to the whole modelling world so I ask your understanding. Can glm models be used for modelling continuous variables? I ask this because I have read that glms are most commonly used to ...
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1answer
29 views

Can I perform a chi-squared analysis with a categorical variable and the means of a continuous variable?

I have one variable that is categorical (with 5 levels), and another variable that consists of either mean or sum scores (0 to 28) due to the way you have to calculate the scores of this measure. Can ...
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0answers
31 views

How best to identify candidate error-prone independent variables

I am working on some blood flow data, obtained through doppler. The resulting dataset is a time series, in which each row consists of the following variables: timestamp vessel cross sectional area ...
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1answer
133 views

Odds ratio of a continuous variable (univariate cox proportional hazards), how to plot that variable against death%?

I have a continuous variable X with which i ran Cox proportional hazards. The outcome was 1=Death, 0=censored/still alive. I have an odds ratio 0.516 for this predictor. 1) How do i interpret that ...
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1answer
54 views

Continuous vs. categorical variables in interaction terms

My analysis includes, among others, three independent variables: X (interest rate), Y (type of rate; it is a dummy), and Z (likelihood of bankruptcy). I have transformed the latter into a categorical ...
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70 views

Banding variables for initial GLM fit, then replacing with continuous versions. Any pitfalls?

I am aware of some of the pitfalls of using banded versions of continuous variables when fitting a GLM (or other model), with a number of discussions on the subject on this forum (and a excellent list ...
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3answers
222 views

Conditional probability of continuous variable

Suppose that random variable $U$ follows a continuous Uniform distribution with parameters 0 and 10 (i.e. $U \sim \rm{U}(0,10)$ ) Now let's denote A the event that $U$ = 5 and B the event that ...
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28 views

Combining two data sets with different weightings, possibly Bayesian Updating?

I am a PhD student and I am currently looking at railway track degradation. As part of this I am finding linear fits of the track geometry recordings against time to give a degradation rate. The ...
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1answer
57 views

Sample size calculation for the comparison of the means of three groups

I have to calculate the sample size for my project. The study is a comparison between three different treatments at three different time points. The outcome variable takes continuous values. We ...
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1answer
35 views

How to estimate rating of a customer?

I have data about customers transactions contains: ratings of customer $r_{ci}$ to service $s_m$ which has quality $q_m$. Quality is assumed to be a real value from [0, 1]. Rating is discrete values ...
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1answer
72 views

Significance of continuous variables

I have a table with several numerical continuous measurements and an indicator column catastrophy ...