# Questions tagged [function]

A mapping between a set of inputs and a set of outputs.

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### Understanding notation for input space

I'm taking the free Caltech machine learning course. I'm having trouble understanding the notation on one of the problems: In this problem, you will create your own target function f and data set D ...
88 views

4 views

### Is it possible to learn a mapping between unpaired time-series data?

I have two time series. One is an actual recording of physiological signals, the other is a binary representation of activations (0 or 1) based on a simulation of the process underlying the ...
33 views

### Transform data domain and maintain mean

I have a dataset, $y$, that is on some arbitrary range. I would like to transform this data to be on the range [-1,1]. This is accomplished using a linear transformation, such as the one described ...
1 vote
67 views

### Standard deviation of a function of random variables

I was a bit confused recently with why two jointly distributed variables will exhibit a smaller scatter as the correlation between the random variables increases (assuming only positive values for the ...
1 vote
89 views

### Is there a way to stretch sigmoid function output

I have an array of values and a value that lies outside of array's max value: arr = [10, 15, 20, 30] value = 150 and I want to make that value less of an outlier, ...
42 views

### Describe a geometrical shape as a piecewise function

Consider a cube filled with random particles. Let's say the particles in cube are rotated around the z-axis through the center of the cube. Here, the rotation is proportional to the height of the cube,...
29 views

### Estimating the sample variance and expected value of a maximization function of multiple random variables

Suppose I have three i.i.d. random variables $X$, $Y$, and $Z$. A model is used to generate $i$ outcomes for each variable that are used to estimate the sample mean and sample variance for each of the ...
183 views

1 vote
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### How to use statistics to speed up row-wise computations on a data.frame?

I have a data frame with 10,000 rows and 40 columns. I am trying to apply a function to each of these rows. For each row, I am expecting to return a scalar which is the value of the statistic I am ...
737 views

### How to weight ranks?

I have a set of responses ranked by my participants. For example, they gave responses A, B, C and ranked them as 3, 2, 1 (or C, B, A). I computed relative frequencies of each responses (A, B, C) and ...
54 views

### What is the equation of a line fitting a log-log model computed in R?

I am currently stuck, wanting to extract a line function from my fitted line on my log-log model. ...
1 vote
25 views

### Why does non-parametric approach break down when the joint distribution is estimated by a finite data sample?

I am currently reading the paper on Gradient Boosting Machines - J. H. Friedman, “Greedy function approximation: A gradient boosting machine,” Ann. Stat., vol. 29, no. 5, pp. 1189–1232, 2001, doi: 10....
78 views

### replacement error when feeding data from function into matrix in R [closed]

I am trying to write a function that creates simulated datasets. The function takes the argument size, being the size of a group, and it is meant to produce a matrix with 100 columns with values 0 or ...