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.

2700 questions
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Recursive curve fitting

I have a few points for which I have to obtain a best fit. (I tried to use the least squares curve fitting method as Robert says, however, since it seems to be fitting rather poorly, any other suitable method would also work for me.) However, the…
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Scatter Plot in Regression

I have an assignment talking about plotting the data points in R3. The data are shown below: no x1 x2 x3 y 1 9 12 7 101 2 3 6 6 66 3 13 14 1 85 4 10 12 7 103 5 4 4 3 47 6 -5 -1 4 19 7 3 8 6 72 8 …
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Endogenously determined variables in regression analysis

I am working on a project with a former professor, and we are considering using two-stage least squares (2SLS) regression to deal with some endogeneity we suspect in our model. To make sure I'm up to speed on 2SLS, I have been reviewing the…
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Unbiased Estimate of Variance

Consider a simple linear regression model for $n$ observations where $$Y_i = \beta_1 X_i + \epsilon_i$$ where $\epsilon_i \sim N(0,\sigma^2).$ I want to show that $$\hat{\sigma}^2 = \frac{1}{n-2} \sum_{i=1}^n \hat{\epsilon}_i^2,$$ is an unbiased…
John
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Regression of y/x on x

I have a simple question but I do not manage to be sure! I would be very grateful if you can confirm me! Do we have the possibility to estimate the following model : $$\frac{y}{x}= \alpha+\beta x+\varepsilon$$ Is there any problem because the…
Pete
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Linear Regression - Predction

With this question I can input data and I can find the linear regression line - but I am totally failing to get the last part - predicting how many hats will be sold in $2017$. How do you do it. Thanks for your help. At a shop, these numbers of hats…
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If X and Z are uncorrelated and Z is normal with mean zero and constant variance, why can I assume Z is zero?

I have a data set that I have used to calculate the coefficients for a linear regression. The data set is of the form $\lbrace x_i,y_i\rbrace_{i=1}^{n} $ Let $$Y = \alpha + \beta X + Z$$ where $\text{corr}(X,Z) = 0$ and $Z \sim N(0,\sigma_Z^2)$,…
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Categorical Variable and Metric Variable

If $Y$ is my dependent variable having more than $2$ categories (so $Y$ is a non-metric/Categorical variable) and $X_1, X_2, X_3\cdots X_n$ are my independent variables which are metric in nature. Now I want to find out which of the $X$ variables…
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How to calculate the linear regression model of function $y=\alpha + \beta k + \beta x$?

I have a linear function $y=\alpha + \beta k + \beta x$ and observation data that consist of pairs of $x$ and $y$. $\alpha$, $\beta$, and $k$ are unknown parameters. I want to estimate the value of $\alpha + \beta k$ and $\beta$. I don't need the…
Yan Li
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Why are the two answers different?

I found exponential regression on Desmos for a few values: I want to find the X value when Y is 40,000. So, when zooming in on 40,000, I see that X is around 160. But, when putting the equation: y=7.4927(1.0695)^x in Wolfram Alpha, I get x =…
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Linear, quadratic and exponential regression

I know the formulas for linear and quadratic regression. Please tell me 1) how to model an equation for exponential regression? 2) if I can use the gradient-point formula for linear regression and similar methods for finding equation for quadratic…
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How to apply the method least squares polynomial of single degree?

Now I am making Almon model. Lag is 3, and polynomial of 2 degree, so I have following linear regression equation $y_{t}$ = $a$ + $c_{0}$$z_{0}$+ $c_{1}$$z_{1}$+$c_{2}$$z_{2}$. I have a list of $y_{t}$, $z_{0}$, $z_{1}$, $z_{2}$ values, how can I…
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Least Square Estimators of a Linear Regression Model

A linear regression model may be written either: $Y_i$ = $\beta_0$ + $\beta_1X_i$ + $\epsilon_i$ Or $Y_i$ = $\alpha_0$ + $\alpha_1(X_i + \bar x)$ + $\epsilon_i$ Use the method of least square to estimate $\hat \alpha_0$ and $\hat \alpha_1$ I am…
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How to find the least square estimators for linear regression model.

I have the linear regression model: $Y_i= \alpha_0 + \alpha_1(X_i - \overline{X})$ Anyway I got through the method for find the least square estimator for $\alpha_0$ and end up with $\sum_{i=1}^n \frac{\alpha_1(X_i-\overline{X})}{n}$ as part of my…
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Expressing Series-Element in Terms of its Index

Consider the following recursion: $$C_{i+1} = a \sum_{j=1}^iC_j + b$$ where $a$ and $b$ are constants. Can series-element $C_i$ be expressed in terms of only its index $i$, $a$ and $b$? In case $C_1$ = $b$, does the answer change?…
Yan Raf