# All Questions

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### How to predict max value of a heavy tailed variable

I have a response variable which is right skewed. There are lot of low values, less than 10 and then extremely large outliers. I want to create a model which can predict the max values that the ...
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What statistical analysis test do I need to run? I want to compare type of downloader (Legal and Illegal) to what type of content they download (Music, Movies etc). In SPSS I have set the type of ...
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### Evaluating a regression model

For classification problems I have been using Neural Networks and measuring Type I and II error using the confusion matrix and its measures as per this resource which is pretty straight forward. ...
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### How to deal with 0 values on the diagonals for a chi-squared test [on hold]

I am performing a chi-squared test in which differently oriented lines cross-cut each other. Because you cannot have two similarly-oriented lines cross-cutting each other, the diagonals on both my ...
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### Need some advice on data analysis

I collected data from 500 participants. Here's an example of the data: Response 1: Age: 25 Gender: Male Choice 1: 1 Choice 2: 1 Choice 3: 0 Choice 4: 1 Choice 5: 1 ... Up to choice 30 Response 2: ...
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### Stata import delimited w/ duplicated variables [migrated]

I have a csv with two identical columns: X,X 0,0 1,1 2,2 I would like to import this into Stata 13, but it does not like importing the second X (since the names ...
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### Bias in predicting survival with time varying covariates

I'm trying to predict survival probabilities with time-varying covariates. My dataset constitutes a variety of subjects who enter the study at different dates and receive multiple follow-ups. For each ...
15 views

### Confidence Interval for a Random Sample Selected from Gamma Distribution

Working on a homework question and having some trouble... Any help would be greatly appreciated. Based on a sample 1.23, 0.36, 2.13, 0.91, 0.16, 0.12 from the GAM$(2,\theta)$ distribution, find an ...
8 views

### Run time analysis of the clustering algorithm

I was reading some notes on ML and clustering and it claimed that the run time of clustering was O(kn) where k is the number of clusters and n is the number of points. I was wondering why this was ...
31 views

### central limit theorem

can I do my statistics work based on the central limit theorem? I need to perform a t-test, ANOVA and multiple regression. my outcome variable is highly not normally distributed (Highly positively ...
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### Name of this simple descriptive method for showing crosstable combination typicalities?

This might be a basic question, but I have no clue what this descriptive method could be named. Simplified, I have a cross-table with Occupations (e.g., doctor, lawyer, engineer) as rows, and Hobbies ...
27 views

### Finding a suitable distribution for data in R?

I have a set of data with summary as below: The data are non-normal and transformations did not obtain normality. Given the data are continuous I have narrowed the range of distribution down to ...
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### Finding parameter bias under omitted variable, with variance covariance notation

Dear CrossValidated community, Can anyone help me to prove the bias in a given parameter of a regression when there is omitted variable? I know to do it using matrices and matrix algebra. For ...
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31 views

### CSV file to numeric [on hold]

I I read a csv file. Now I need to convert it to numeric, but how? data = read.csv("c:/osz.csv", sep=";", header=FALSE, dec=".") ...
21 views

### How to account for autocorrelation in a multiple linear regression?

I'm trying to create a multiple linear regression with water temperature change as my response variable and four numeric explanatory variables (that influence temperature change). Each numeric ...
10 views

### Comparing two distributions using Generalized method of moment estimation

If I consider a data X, I want to fit a distribution Y which has a density f(x) but It's not possible to express the moments of Y as function of the parameters. My problem is : 1- to estimate the ...
8 views

### Issue With class imbalances in classification problem

I am working on a word sense disambiguation problem. Specifically, I am using decision lists to classify the ambiguous word. Decision lists work in the following way. The quantity ...
8 views

### Standardizing inputs for CART

I know I do not need to standardize the predictor variables before applying CART but would there be any adverse effects to doing it anyway? I'm comparing CART to a linear regression where I did ...
22 views

### ldentifying observations based on deviation from the conditional mean

Consider bivariate data consisting of correlated variables (r ~ 0.9). It is known how both the variables are calculated. Each observation is identically distributed but non independent. Also, the ...
16 views

### Time series prediction: visualising path uncertainty region

I am predicting a time series' future evolution and am evaluating the path uncertainty using bootstrapping. Is there a good way to visualise the uncertainty that goes beyond simply plotting a pair of ...
131 views

### General method for deriving the standard error

I can't seem to find a general method for deriving standard errors anywhere. I've looked on google, this website and even in text books but all I can find is the formula for standard errors for the ...
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### Probability of object collision

I've been searching for a few days on a number of sites but I can't seem to find a good answer for this. I'm developing a collision detection program using Unscented Kalman Filter and predicting ...