regression analysis

  1. F

    Two dummy variables are mutually exclusive

    Hello all, I have a problem for a university assignment that two dummy variables are mutually exclusive. The task is to estimate what can increase certain diseases in dogs using regression. In the sample there are several factors (Lives in city yes/no, age, male/female etc....). Then there is a...
  2. T

    How is conditional main effect interpreted when there is interaction?

    I have a question about multiple regression. May I kindly ask how should I interpret the conditional main effect when the interaction is 0 and the coefficients have opposite signs, more specifically if one of the interaction term contains zero such as angle or time. Please see an example...
  3. M

    Negative correlation, but positive effect in multilevel regression

    Hello, I am doing a longitudinal multilevel analyses. I am researching the impact of certain restricting abortion policies of US states on the number of abortions. Furthermore I control for the characteristics of these states. One of these characteristics namely poverty rate of a state, has a...
  4. U

    Which test to use? one predictor variable and 3 dependent variables

    Hello, I'm hoping someone can help me. I am conducting research for my thesis looking at relationship between social connectedness (IV), and diabetes distress, diabetes self-management and perceived competence (DVs). All are continuous variables measured on self-report likert scale...
  5. R

    Help deciding which spss functions to use

    I'll start off saying that stats in general has never been a strong point for me :D The variables i am using are; Gender Age Relationship Status Number of dependants Profession Neuroticism (Higher score = higher neuroticism) Affectivity (Higher score = positive; lower...
  6. A

    De-trending before regression analysis

    I'm currently analysing two sets of time series data (monthly temperature and forest cover over a 10 year period). I first ran a Mann Kendall on each variable (they're non-normal) after removing seasonality, and found that they both show a significant increasing trend - vegetation faster than...
  7. E

    Multiple Linear Regression Assumptions

    Hi guys! I am gonna model multiple linear regression. Do you think that normality of residuals assumption is met according to the P-P plot? Also, consider the homoscadasticity assumption according to the scatter please. I am writing my Bsc. thesis, what should I do if these two assumptions...
  8. L

    Sufficient linearity between predictor and response variables?

    Hello everyone, for a multiple regression I am currently trying to understand if there is sufficient linearity between my predictor and response variables to see whether I can carry on with a regular linear regression. I have three models, with one dependent and the same three...
  9. B

    FE, RE, OLS Cluster?

    Hi all, I've a question which regression model to use? I've the following model: Taxavoid= PC + Before/after + PC * Befor/after tax avoid = continious where PC is ratio variable of political party/ i coudl have used 1 or 0 (REPvsDEM) but, I use ratio, more info. PC= REP / (DEM+REP) so ratio...
  10. L

    Can an odd ratio be as low as <0.001?

    With a 95% CI of <0.001 to >999.999? Any idea what could be wrong? (Sorry about the french output, will gladly provide more info if needed) Thanks a lot!
  11. N

    Best method to determine future success or to determine best linearity?

    Long time viewer, but first time poster, so excuse me if i'm in the wrong place please. Anyway, I am working on a project that is pretty interesting. Through data mining, I am able to gather a ton of investment portfolios. Each portfolio has the obviously related statistics, including total...
  12. V

    Can I remove these outliers?

    Hi, is it acceptable if I remove the outliers with charges above 55k for this regression analysis? Or is there any other option to minimize their impact in the model? Thank you
  13. N

    What Model or Calculator should I use to set the right target?

    I have a production target in which 90% of widgets must be completed within 2 hours. The production process has two main components. Process A + Process B (together these have to be completed within 2 hours, 90% of the time). (quick note: Process A is the simpler process) I want to establish...
  14. A

    Multiple Imputation in SPSS: What to do and report

    Hi everyone :) I'm currently working on a research question where there are 2 categorical predictor variables (one with 2 levels between subjects, the other with 7 levels within subjects) and one continuous response variable. I want to conduct a simple repeated measures ANOVA in SPSS. The...
  15. A

    Do I need to rescale variables to compare coefficients.

    I'm running a regression analysis. My "Y" variable is Yearly_Spend while my "X" variables are Time_Spent (on website in minutes) and Length (of membership in years). Right now my results show Years has a bigger impact on Yearly_Spend. Do get a true apples to apples comparison of the...
  16. A

    Different coefficients from regression and trendline equation

    I have two variables 'x' and 'y'. I took the natural log of the 'y' variable and then plotted the ln(y) vs x on a scatterplot in excel. I added a logarithmic trendline which seems to fit perfectly. The line equation is y = 1.1282*ln(x) + 12.183 with an R-Squared of 89%. However when I run the...
  17. D

    Logistic regression or something else?

    I have a dependent binary outcome and 6 independent variables. These are measured in the same group of people at two moments in time in a descriptive longitudinal study. I am assessing whether these independent variables increase the likelihood of achieving the binary outcome. I know that I...
  18. S

    regression coefficient as average effect

    In OLS, given the regression equation y = B0 + B1X, why do I often read that B1 represents the average effect of a predictor? I don't get that. For example, data <- data.frame(sex=c("male","female","male","female","male","female","male","female"), DV=c(22,32,34,16,66,34,77,23)) The average...
  19. J

    multivariable regression equation with interaction terms for difference-in-difference method

    I am doing a difference-in-difference analysis on a set of survey data for a health education program and I need to find statistical significance for the difference-in-difference estimate. I know that I find this using a regression. I need to use a regression in a mixed logistic model including...
  20. J

    Why does the “linear regression t-test” return a p-value (two-tailed) from regression that is twice the p-value from ANOVA? (Binary predictor)

    I'm using the "linear regression t-test" guide at The guide shows calculating t =b1/SE, where b1 and SE are provided by the regression function (here lm() - using R.) The guide shows the p-value gets doubled as this is a two-sided test...