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...

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:

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...

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...

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...

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...

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...

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...

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...

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

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...