linear regression

  1. E

    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...
  2. A

    [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...
  3. J

    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...
  4. 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?
  5. 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...
  6. P

    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...
  7. E

    Sign differences in coefficients arising from using ordinal vs continuous data

    I run a simple OLS regression: y=a +bx+.....+e, I obtain an estimate of b<0. Prior researchers running the a similar regression obtain an estimate of b>0: I'm trying to reconcile this difference. The only methodological difference driving our results is the following: In my study...
  8. R

    Dealing with Log(0)

    Dear all, I’ve been stuck for quite some time with a problem that relates to use of log-scale with values that equal zero. My data comes from an experiment in which five different instruments (one of them using the reference method) take two measurements of a given sample’s signal emission. A...
  9. R

    log(0) should have a real value!!!

    Dear all, I’ve been stuck for quite some time with a problem that relates to use of log-scale with values that equal zero. My data comes from an experiment in which five different instruments (one of them using the reference method) take two measurements of a given sample’s signal...
  10. F

    Beta significance level in one model the same as the R-squared-change significance

    I am very new to statistics, so apologies in advance if I have not explained this clearly. I have run two types of linear regression: - The first contains 4 independent variables, all entered at the same time. - The second uses "blocks" to enter 3 of the independent variables in the first...
  11. M

    Which analysis represents better the "worse-ness" of my linear regression?

    Hello all, If I have two sets of data points, for instance: 1 10 2 14 3 17 4 12 5 19 and 1 10 2 14 3 17 4 12 100 112 The linear regression is bad for the first set and good for the second, if you look at R^2, but it is still a bad line. I was told that...
  12. N

    Have 4 dependent and 10 independent variables - which test should I use?

    Hi all, I'm interested in the potential effects of water pollution on feather color of a bird. For this, I calculated 4 color variables for each individual (brightness, hue, blue chroma and UV chroma), which are my 4 dependent variables. My independent variables (explanatory) are the...
  13. A

    Statistical analysis and playing around with incidence rates

    Dear TalkStats Members, I am a bloody noob to R (used SPSS till now) and decided to learn R now. My first quest would be following: I have incidence rates in an Excel file for a disease, which look quite like this: Year Total Male Female 2003 0.3 0.4 0.2 2004 0.3 0.3 0.3...
  14. Junes

    Many predictors relative to cases, want to identify interesting ones

    I've been helping a colleague with his research project. He is looking at the trustworthiness of profile texts. He is analyzing text entries using the LIWC tool, which generates around 90 dimensions based on text input (positive/negative affect, pronoun use, etc.). Most of it on the ratio or...
  15. H

    Linear Regression coeffiecients used in Exponential Regression

    I have a decay curve (y) with values 1, 0.75,0.64,0.54,0.46. The x values are 1,2,3,4,5. First a simple linear regression was performed (y =mx + b). Now the slope and coefficient of this line are used in the following exponential equation to predict the y values for x = (6,7,8). Exponential...
  16. A

    Stationary data first after the 2-order/3-order difference on LN(variable)

    I want to make an Linear Regression. Dependent variable: GDP Independent variables: Net exports and Debt and some control variables All variables are seasonal and calendar adjusted. The aim it to see the effects of Next export and Debt on GDP for different european countries. I will make...
  17. G

    Cave Temperature Analysis, Real life management issues.

    Hi, I've taken math course's up to Calc III and Diff Eq, but never a statistics course. So I was hoping this forum could help me. I am working with 10+years of temperature data taken from several loggers throughout a cave system. The loggers record temperature every 30mins, which I have...
  18. A

    transformation on variables

    I run simple linear regression, and saw that my residuals not distributed normally. my dependent variable histogram was as log-normal, i did a log-normal transformation to him. After that i run linear regression with log(dependent variable), and got results. I attached the results. what do you...
  19. A

    linear regression without intercept with dummy variables

    Hello, i run simple linear with one dummy variables and no intercept. i would like to understand the meaning of this. for example, my beta1=1.2, then if my dummy variable equal one, then y=1.2, but if my dummy variable equal zero, then y=0 ??? i know it's not right, what i should do? i know...
  20. H

    Linear Regression

    A simple linear regression analysis resulted in b0 = 40 and b1 = 3. If one of the observations in your data set has a value of Y=14 and X=8, what is the residual for this observation?