regression analysis

  1. 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!
  2. 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...
  3. 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
  4. 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...
  5. 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...
  6. 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...
  7. 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...
  8. 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...
  9. 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...
  10. 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...
  11. 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...
  12. P

    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...
  13. T

    Regression coefficient interpretation

    Hi, i have run a regression to estimate the impact of couple of variables like growth rate, company size or leverage on the profitability of a firm. I know that if e.g. the regression coefficient for growth is 0,5 a 1% increase in growth rate would yield a 0,5% increase in profitability if...
  14. T

    Why are so many variables in my regression significant?

    Dear everone, For my research I am trying to define the impact of certain elements on a company's goodwill impairment. For my regression analysis I deflated the following variables by the lag total assets: - gdwlia (dependent variable) - ROA - BM - difference in turnover between year t-1...
  15. R

    Multiple Linear Regression: to split or not the data

    Hi all, I'm currently modelling running performance using multiple linear regression. The data has GENDER and AGE as inputs amongst others, the target is RACE_TIME. I've partitioned the data into training and test for cross validation purposes. I've tried a couple of approaches 1) to generate...
  16. C

    SPSS Complex Problem or at least it seems as such

    Here is the issue. I ran a logistic regression a time variable (time to surgery) had a trend of increased infection. Great right. Done? No. This is where SPSS gets tricky and why I might just abort back to SAS like I do sometimes. But lets see. I ran a graph for cumulative infection count...
  17. U

    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...
  18. M

    How to split residuals into groups for the Brown-Forsythe test

    I have the following data id 1 2 3 4 5 6 7 8 9 10 11 12 num. responses 16 14 22 10 14 17 10 13 19 12 18 11 cost 77 70 85 50 62 70 55 63 88 57 81 51 I fitted the linear regression model and I got the following residuals: 5.22478992, 4.76260504, -6.38865546...
  19. T

    Interpretation of my results (Significance varies a lot)

    Hi, I have a problem with the interpretation of my results from a multiple linear regression. I want to evaluate the impact of a policy change (X) on an economic indicator (Y) and have included various covariates in the regression (6). The policy change occurred in 2015 and I have data from...
  20. K

    Variable that should appear significant is insignificant

    As part of my University research project, I have decided to study the impact of Immigration on house prices but find that the immigration Variable that should be statistically significant according to literature appears to be insignificant. I don't know whether this was down to the method I...