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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27 views

Is any term to describe the probability density function (pdf) of $f \in C[a,b]$ or $X \in R^\inf$? [on hold]

We do know that there exists probability density function (pdf) of $X \in R^n$. But I doubt whether there is if $X(t)\in C[a,b]$, assuming that $X(t)$ is i.i.d during different time. An intrinsic ...
1
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1answer
26 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 ...
0
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0answers
20 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 ...
0
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0answers
29 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 ...
3
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2answers
63 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}) + ...
2
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2answers
53 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 ...
0
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1answer
24 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 ...
0
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1answer
32 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 ...
1
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1answer
22 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 ...
0
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0answers
4 views

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 ...
1
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1answer
18 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 ...
2
votes
1answer
42 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. ...
1
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0answers
18 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 ...
0
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1answer
34 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. ...
0
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0answers
17 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 ...
1
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0answers
18 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 ...
0
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1answer
23 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 ...
1
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1answer
56 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 ...
2
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2answers
51 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 ...
1
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1answer
71 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 ...
1
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2answers
63 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 ...
1
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1answer
46 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 } ...
1
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1answer
128 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 ...
1
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1answer
33 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 ...
1
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1answer
26 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 ...
2
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0answers
28 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 ...
0
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1answer
114 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 ...
1
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1answer
41 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 ...
0
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0answers
62 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 ...
8
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3answers
215 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 ...
0
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0answers
24 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 ...
0
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1answer
40 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 ...
0
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1answer
31 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 ...
1
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1answer
68 views

Significance of continuous variables

I have a table with several numerical continuous measurements and an indicator column catastrophy ...
1
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2answers
51 views

Does clustering need scalar data?

I am trying to cluster 43,000 individuals on about 50 variables. The data contained in the variables are minutes of a radio shows which people listened to in the range of 0 - 3,000,000 minutes. My ...
1
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0answers
56 views

To BIN or not to BIN a continuous data to get a Fragment Size Distribution ?

I have a data set in excel of almost 6000 entries (quantitative and continuous => P(X=x)=0, I mean the possible values for my continuous random variable X are uncountably many). Each point will ...
0
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1answer
29 views

Continuous predictor of a significant difference on another scale at T1 and T2

I was wondering if anybody could point me in the right direction for a statistical test. I’m looking whether a continous variable (e.g. a personality variable) predicts a significant difference ...
0
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1answer
86 views

Measure of association between non-dichotomous ordinal variable and continuous variable

I have to collect and then analyse a large dataset. A particular data input (continuous variable) is laborious to collect and I believe that an ordinal category (1,2,3,4) would correlate closely with ...
4
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1answer
324 views

Why is this random variable both continuous and discrete?

The waiting time, $W$, of a traveler queuing at a taxi rank is distributed according to the cumulative distribution function, $G(w)$, defined by: $$G(w) = \begin{cases} 0 & \text{ for } ...
1
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1answer
101 views

Analyzing relationships between ordinal and continuous time series data

I have two sets of time series data - roleTrajectories & normalizedDegree. The former data set contains ordinal rankings of subjects' positions within a network at 13 time periods. The latter data ...
0
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0answers
24 views

continuous norming

I am said to apply continious norming to my data (test scores testing children). I have not found any freely available information about this process. I have found out that: 1) norming is based on ...
3
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1answer
83 views

Bayesian linear regression with continuous and binary covariates

I am interested in learning more about applying Bayesian linear models for covariates some of which are continuous and some are binary. What is the appropriate terminology for such models so that I ...
0
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0answers
29 views

Testing for a 3-way interaction between a within-subjects factor, a continuous IV and a categorical IV in SPSS

I'd like to test whether the moderating effect of a (continuous) personality variable on the effect of an experimental manipulation differs between conditions. Does anyone know how to go about this in ...
0
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0answers
30 views

split plot with continuous sub-plot factor?

Question in a nutshell: In a split-plot design, can factor B, the treatment applied to the subplot, be a continuous variable, and can there only be one block?(I read that blocks in split-plot designs ...
0
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0answers
37 views

Predicting continuous response with a mix of categorical and continuous variables

What regression method should I use to construct a model predicting a continuous response with a mix of categorical and continuous variables? I would do this with SPSS (16.0) and was thinking of using ...
13
votes
3answers
390 views

Uniform random variable as sum of two random variables

Taken from Grimmet and Stirzaker: Show that it cannot be the case that $U=X+Y$ where $U$ is uniformly distributed on [0,1] and $X$ and $Y$ are independent and identically distributed. You should not ...
0
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0answers
52 views

Appropriate classification model for combination of continuous, binary and categorical inputs

I have a binary classification problem for classify my samples to two classes (class_1 and class_2). I have different kinds of ...
0
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0answers
22 views

R [nlme] Incrementing / Adding units to continuous covariates?

I'm trying to find out how I can change the beta estimates for a continuous covariate in my model from 1-increment to another increment. For example, if I have age in the model, and I want to ...
0
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0answers
26 views

Methods for predictive modeling on continous target

I am trying to put a continuous target into predictive modelling method. The target is an amount that can range from 0 to unknown. I have roughly 1000 records (for modelling and validation ...
3
votes
1answer
371 views

How to transform continuous data with extreme bimodal distribution

Is there a way to transform a continuous predictor variable (grant) that has a bimodal distribution into a normal distribution (see density plot below)? I have tried log(x+c), z-score and inverse ...