# Tagged Questions

The mathematical concept of a function. See http://en.wikipedia.org/wiki/Function_(mathematics)

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### How to extract distribution of r.v. $X$ from probability generating function of $X$?

How to extract distribution of r.v. $X$ from probability generating function of $X$? The p.g.f. of $X$ is: $$G_X(t)=\sum_{k=1}^{\infty}t^kP_X(k).$$ That is, if $G_X(t)$ is known, then (how) can one ...
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### Minimizer of a function containing response and predicting variables

Can anyone please give me the expression of the "minimizer" of $$\sum_{i = 1}^n \vert y_i - b x_i \vert + \sum_{i = 1}^n (y_i - b x_i)^2 \quad \quad ?$$ I am unable to find this expression on the ...
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### Terminology for a 1-d summary of a high-dimensional space?

Overly pedantic question ahead. Suppose I have a huge matrix M that has a row for everyone who was at Disneyland on some particular date, a column for the person's ...
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### What does this evaluation function mean?

I am solving a prediction problem where I am supposed to predict the number of clicks, given some historical Data. I am told that my predictions will be evaluated by a normalized weighted mean square ...
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### Could not find function in R? [closed]

I am getting the error: Error: could not find function "rlm" where rlm Why isn't R working for certain functions? I wrote fit<-rlm(z~cbind(time(z),time(z)^2)) Error: could not find function ...
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### How to find the mode of a probability density function?

Inspired by my other question, I would like to ask how does one find the mode of a probability density function (PDF) of a function $f(x)$? Is there any "cook-book" procedure for this? Apparently, ...
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### Algorithm to identify a correct input for only one number [closed]

Hello I'm hoping that you good folks here at CrossValidated can help me with this. I'm looking for an algorithm that takes an integer as an input and returns two types of values. One type of value ...
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### Implication of Hazard Rate?

So from my understanding, the hazard rate is not a probability but a rate of an event happening at any one period of time. Can someone please tell me the implications of a hazard rate value. Would ...
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### Learning a spatial function

I have some observations of a variable y, that varies spatially. For each observation, I also have a lat, long tuple. I have some 50 or so observations. Besides conducting some exploratory analysis ...
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### Apply function generating random numbers to a matrix (R) [closed]

I have a function which basically creates a random number. Now I want to apply the function to a matrix for given conditions to replace the value in the matrix with the random number created by the ...
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### What function best describes this plot?

The X and Y have values only between 0 and 1.
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### Validating sameness or difference of a relationship

I am measuring a response variable Y(x,t) which theoretically is a function of both time (t) and space (x). I have measurements for Y as t varies for different spatial points x. On inspecting visually ...