Questions tagged [regression]

This tag is for questions on (linear or nonlinear) regression, which is a way of describing how one variable, the outcome, is numerically related to predictor variables. The dependent variable is also referred to as $~Y~$, dependent or response and is plotted on the vertical axis (ordinate) of a graph.

Regression is a statistical measurement used in finance, investing and other disciplines that attempts to determine the strength of the relationship between one dependent variable (usually denoted by $~Y~$) and a series of other changing variables (known as independent variables).

Types of Regression –

  • Linear regression
  • Logistic regression
  • Polynomial regression
  • Stepwise regression
  • Stepwise regression
  • Ridge regression
  • Lasso regression
  • ElasticNet regression

The two basic types of regression are linear regression and multiple linear regression.

The general form of each type of regression is:

  • Linear regression: $~Y = a + b~X + u~$
  • Multiple regression: $~Y = a + b_1~X_1 + b_2~X_2 + b_3~X_3 + ... + b_t~X_t + u~$

Where:

  • $Y =~$ the variable that you are trying to predict (dependent variable).
  • $X =~$ the variable that you are using to predict Y (independent variable).
  • $a =~$ the intercept.
  • $b =~$ the slope.
  • $u =~$ the regression residual.

There are multiple benefits of using regression analysis. They are as follows:

$1.~$ It indicates the significant relationships between dependent variable and independent variable.

$2.~$ It indicates the strength of impact of multiple independent variables on a dependent variable.

Reference:

https://en.wikipedia.org/wiki/Regression_analysis

This tag often goes along with the tag.

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How do I fit multiple curves with same fitting parameters?

I have three different curves for three different temperatures. The expression I'm trying to fit the data to looks like this: $E_b=E_0(1-\tau/\tau_0)^{\alpha} (1-T/T_m)$. So I'm trying to fit the energy barrier ($E_b$) data to stress and want same…
anikfaisal
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Find an equation of the form $y= a e^ {x ^2} + bx^3$ which best fits the points $(−1, 0), (0, 1), (1, 2)$

Find an equation of the form $y= a e^ {x ^2} + bx^3$ which best fits the points $(−1, 0), (0, 1), (1, 2)$ I am given the hint don’t form a summation – explicitly form S with three terms, and find the derivatives. I have tried using the formula…
Jac Frall
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Regression with predictors that are sometimes undefined

I have a model M that takes input X and outputs Y, and I'm trying to predict how the mean of Y will change as parameters of the model P vary, given a distribution for X and some samples of the mean of Y from runs of the model with given parameter…
PeterW
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Linear Regression Computation as $y = ax$

I got a process which can be modelised as a Linear Regression matching an $y = ax$ equation. I can find on the internet computations to match an $y = ax +b$ equation like this $$ b = \frac{\sum y\sum x^{2}- \sum x\sum xy}{n(\sum x^{2})-(\sum…
cz3ch
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Interpretation of change in log in regression

I have build a time series regression with the formula: $$\Delta\log A = \alpha+\beta\Delta\log B $$ I have found $\beta= -0.05$. I can't seem to figure out how to interpret this number. I know that in a log-log regression the coefficient denotes a…
Cardinal
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Least Squares Criterion Problem

Problem: Show that the least squares criterion applied to the "intercept-only" model, i.e. $y_i = \beta_0 + \epsilon_i$, $i = 1, 2, ..., n$ results in the least squares estimator of $\beta_0: \hat \beta = \bar y$ I'm not sure where to begin with…
Trever
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Consider a regression model

Consider the regression model: rcon, the (excess) rate of return on a portfolio with construction industry assets, rmrf, the (excess) rate of return on a market-wide well-diversified portfolio, $$ \mathrm{rcon}_i = \beta_1 + \beta_2\mathrm{rmrf}^2_i…
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Multidimensional Linear Fit

As shown in the attached picture, I have different measurement points which belong to certain linear functions with different slopes $m$ and different $y$-intercepts $n$. For every curve I have a fixed $m$ and $n$. Via MatLab, I want to find…
Dan
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How well does a model fit a subset of the original dataset?

A linear regression model has been created based on a dataset with observations which can be sorted into several different categories. I have been asked to assess how well this regression model (which was created using the entire dataset) fits the…
Greg
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Is there a curve fitting algorithm that focuses on fitting one part of the curve well rather than trying to make a good general fit?

One use case for this would be multi-exponential decay fitting, I'm talking about functions of the type $ \displaystyle f(t)=\sum_i^N a_i \cdot e^{-t/\tau_i} $ It would be awesome to have a fit algorithm that basically performs a mono-exponential…
Keno
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Problem with linear regression normal equations when a coefficient should be zero

I am having trouble using the linear regression normal equations to minimize a function of several variables. The minimization solution is : $$\beta = (X^TX)^{-1}X^TY$$ where $\beta$ is the coefficient vector of a function to minimize…
Frank
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How is the error term of Radial Basis Function (Network) found?

How is the error term of Radial Basis Function (Network) found? Such as in: $$\min_W I(W)=\frac{1}{2N} \sum_{i=1}^N ||W g(x_i)-y_i||^2+ \color{red}{\frac{\beta}{2} \sum_{j,k} |W_{jk}|^2}$$ Then how does one discover the error term? $W$ is the…
mavavilj
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Why can't I get an accurate polynomial equation for these data points?

I have 30 data points that I have digitised from the red dashed line in the graph below. My goal is to find an approximate equation to represent the line. I have tried to get a 6 degree polynomial trendline through Excel for these points, but if I…
david_10001
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simple regression variables to multiple regression problem

I'm a beginner at statistics. While doing the analysis, I did a simple regression and check out that some variables have low p-value. Therefore I thought they are influential variables for dependent variable. So I did Multiple regression with…
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How do I calculate the coefficient of determination, $R^2$, using the following data?

Supposing that a simple linear regression has quantities $N=20$, $\sum_{i=1}^{N}y_{i}^{2}=5930.94$, $\bar{y}=16.035$ and $SSR=666.72$.