# All Questions

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### predict function and categorical variables in R

This is more of a general question about how the predict function treats categorical variables and how to interpret the output from predict. I have a zeroinfl model to predict the number of animals ...
15 views

### How to cluster users based on search terms

How to cluster based on what users are searching on I'm working on an app which includes search functionality: a search box that allows a user to enter text and search the entire site. I have access ...
152 views

### Real life examples of distributions with negative skewness

Much along the lines of the "real-life examples of common distributions" I'm interested if anyone has any pedagogical examples used to teach negative skewness? There are plenty of canonical examples ...
9 views

### Simulating EM versus listwise deletion--unexpected results

I'm preparing a presentation on missing data strategies and conducted a simulation to compare listwise deletion (LD) to the EM. Here's what I expected based on the literature: Standard errors will ...
37 views

309 views

### Hints on this computer vision / machine learning problem

I've been working for a while on a pet problem. The task is to identify and segment out the dark lines and possibly the wiggly ones too. I'm not looking for anyone to solve this problem for me...I'm ...
3 views

### Compute the user and item features in SVD++

I have a sparse matrix. There is lots of missing data. Hence, I can't use SVD naively. I read Koren's SVD++ paper. I'm confused as to how the $q_i$ and $p_u$ vectors are determined. $q_i^Tp_u$ is ...
60 views

### From a Bayesian probability perspective, why doesn't a 95% confidence interval contain the true parameter with 95% probability?

From the Wikipedia page on confidence intervals: ...if confidence intervals are constructed across many separate data analyses of repeated (and possibly different) experiments, the proportion of ...
16 views

### Sequential importance sampling for multi way contingency table

Full disclosure: this is a homework problem. I'm having a really hard time understanding the algorithm for applying SIS to contingency tables or what it even means to do sequential importance sampling ...
I've come across a question where I have an MA(1) process like so: $X_t = b_t - 0.4 b_{t-1}$ (where $b_t$ is a white noise process and $t$ is the time index) The question asks me to find $\phi_{11}$ ...