linear regression

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    How do I determine the minimum number of observations needed per category in categorical predictor variables?

    When conducting a simple linear regression analysis with one categorical predictor variable and power projected at .80, G*Power suggests a minimum sample size of n = 55. Now, assume that the predictor has three categories, and that I obtain 55 necessary responses. What does it mean for the...
  2. T

    Compare independent variables among different models with same dependent variable

    Hello, I am running three multiple linear regression models. In all three, the dependent variable is the democracy index score of a range of countries over several years that the EU has agreements with. I use three independent variables in each model. Two of those are the same in each model: a...
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    Multiple Linear Regression

    Hello, I am an MBA student and require help doing a multiple linear regression analysis using spss, check if I uploaded the data with the correct options and how to interpret the data and results. I have 2 independent variables and 1 dependent variable. Thanks!
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    How to interpret log differences in a partial log-log regression

    I'm currently trying to understand the relationship between firm performance and various independent variables (e.g. firm size, firm profits..). Now, the regression I'm estimating looks like the following: Δlog(firm_performance) = α + β1 Δlog(firm_size) + β2(other_variable) + ε Where Δ...
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    Linear regression assumption

    How can I handle heteroskedasticity?
  6. O

    checking assumptions

    Hi, I am not really able to understand whether the basic assumptions of linear regression are met (I'm kind of a novice). I have a dataset that is big enough (as far as I understand), a series of significants coefficients (both individually and togheter) and an adjusted R-squared over 0.9...
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    Linear vs nonlinear regression doubt

    Hello, I am currently working on a study about how much time a chess engine should think per move in a chess game. The inputs (known data) would be how much time is left (in seconds), the evaluation of the engine (centipawns) and the move that is being made. My question is: is it a multiple...
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    What test should i use? THESIS HELP!!

    Hi, I am currently studying Zoology at university. I am currently in my final year conducting my dissertation. I have completed my data collection and I am now on to my statistics. My dissertation looks at the relationship between light intensity and growth rate in marine sponges. I have 5...
  9. O

    Minimum Sample size for multiple linear regression

    Hi, I tried to calculate the minimum sample size for multiple linear regression. I tried to check the sample size for predictors=4, effect size f=0.2/d=0.2, sig.level =0.05, power=0.8 1. When I checked the power of the entire model (F power) n=304 2. When I checked the power of one...
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    How to report linear regression results (Matlab)?

    Hello, I performed a simple linear regression analysis in Matlab and am unsure about how to report the results. I definitely mention the coefficients and the p-value, but do I mention the t-statistics as well? And if so, how exactly? This is an example Matlab output:
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    Logistic regression curve looks like linear regression

    Hi, I performed a linear as well as a logistic regression analysis (both with Matlab) and plotted those. Now the logistic regression curve is very linear and can be described by the same function as the linear regression. I explain the linearity by the fact that it is only a very small fraction...
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    Adequate subsample size to represent sample regression

    I am performing an engineering analysis to find out the effect of earthquake on concrete buildings. Analysis applies earthquake forces on building model for 50 earthquakes, resulting into separate 50 analyses. Earthquake intensity is independent variable of study. building drift, extracted from...
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    Linear regression in genetics, interactions

    Dear All, I am searching for the association between a phenotype (PHEN) and the additive genetic model (ADD, with the values 0,1 and 2) with two adjustors, Year of Birth (numeric) and COUNTY (catergory). The data has been weighted for the year of birth. In R I use the next command...
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    How to Test for Co-integration with the Augmented Dickey-Fuller Test?

    Hi everyone. The table above contains two example factories that I would like to test for cointegration using the augmented dickey-fuller test. I intentionally use this short time series because I want to do the calculations by hand. Below you will see my attempt to carry out this procedure and...
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    Linear modelling

    Hi, I need some help with a modeling query: I have fit 100,000 linear models: M ~ age + age^2, M is the frequency. I found 2,000 models were significant, but would like to narrow it down to find the most ‘extreme’ cases. Is this possible? Does anyone have any suggestions or any references...
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    [Linear Regression] Regression with aggregated or separated years?

    Hello to everyone! :wave: I should do some regressions but i've an important and simple question... my dataset have this structure: |geographic_area|year|sales|popolation| Spain 2000 40 1000 Spain 2001 30 2000 Spain 2002...
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    Importance of vars in linear regression (R)

    I have a question that is and R question and a statistical question: I am analysing sales of a retailer. These sales are related to some vars: var1, var2, var3.., varN Most of the vars are continuos. I want to analyze the relationship between sales and the vars. I have made a linear...
  18. L

    Trichotomizing an Independent Variable

    In SPSS, how does one go about trichotomizing an independent variable such that about 33% are in each of the three groups?
  19. T

    Multiple regression V.S. Bivariate regression

    Hi there, I'm interested in the effect of several variables on severity of schizophrenia symptoms. I want to look at the effect of 9 predictor variables in a regression model. Severity of schizophrenia symptoms is the outcome variable. My sample size is about 60. My 9 predictor variables...
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    Linear Regression: Significance levels/Finding equation of fitted regression lines

    I did an exam recently and I am looking for a solution to a question which no matter where I look, I can't find out how to do it. It doesn't help I'm not very good at stats hence the post here. Could someone maybe point out a Youtube video that deals with similar problems. It's specifically part...