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10 views

Help required in controlling for socioeconomic factors when mapping travel behavior

Background I have cleaned disaggregate travel data down to a household level (of about 75% of households) and socio economic data aggregated into 100-200 household blocks. What I'm wanting to do is ...
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0answers
5 views

For industrial statistical process with sparse data, what is the maximum allowable sparseness?

Suppose you have a factory that does statistical process control by randomly selecting workpieces and measuring them. Suppose you've got 1000 workpieces in a month, and each piece starts as raw ...
2
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1answer
51 views

Quality Control Chart for non-normal distributed data

I am interested in building quality control charts for time series data where every data point has different gradation within the range of 0 to 1. For example first data point X1 may be 0.1, 0.2,..,1 ...
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0answers
11 views

multivariate control chart

I am trying to build a multivariate control chart but I did not find any good explanation of how to do that. Starting with $x_0$ a part of the samples that are in control I compute $\mu_0$ and ...
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0answers
67 views

Numerical optimization of Bellman equations for stochastic dynamic programming problems

I am trying to carry out the discretized process suggested by the authors in this paper, i.e. the numerical optimization, and would be grateful for some pseudo code or better still R code that might ...
2
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1answer
92 views

Using control variables in Difference in Difference method

When random experiments are conducted, 'baseline data' are usually used as control variables in order to increase precision. How about control variables in Difference in Difference method? What I ...
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1answer
49 views

Common or regional time dummies as controls: Does it make a difference?

I am analyzing policy diffusion using panel data, and the inclusion of temporal controls substantially influences my results. I'm wondering if it can theoretically make a difference for the estimates ...
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0answers
14 views

Scale of control variable in ANCOVA

I am new to the field of ANCOVAs. I want to check if two groups differ in three quantitative variables. At the same time I would like to control for gender and diagnose (6 categories). Is it ...
2
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0answers
92 views

How does my questionnaire analysis plan sound?

I will soon have the results of a questionnaire that I have carried out, and I have made a plan on how I will analyse the data. I was hoping that someone could comment on my plan to advise me. About ...
3
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1answer
194 views

How to explain control variables and interaction effects

I'm a bit stuck on running a GLM between 3 continuous variables in R. I can't make them categorical as it removes the significance. I have two questions. I'm analysing data on eggs. I had read that ...
2
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2answers
45 views

Balancing gender in an experiment

Say a study aims to see if two variables A and B are correlated in the general population. It isn't clear to me how extraneous variables like gender should be treated when the sample is selected. Each ...
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0answers
35 views

How to assess whether IQ predicts emotional experiment more at time 1 or time 2 controlling for covariates?

I have the following data set of a two-wave longitudinal study in educational psychology. A group of 400 people did some questionnaire on IQ, personality and two different emotional states (sadness ...
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0answers
25 views

Controlling for respondents' propensity to rate high/low or moderate/extreme

I am doing a simple linear regression to test the relationship between voters' self-reported policy stands and their approval ratings for two hypothetical presidential candidates in a simulated ...
1
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2answers
146 views

How to determine the correlation between 2 time series while controlling for a 3rd?

I would like to determine the relationship between two variables after controlling for a third. Specifically, I want to know if the prices of mercury and gold over time are correlated with each other ...
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3answers
1k views

What does “all else equal” mean in multiple regression?

When we do multiple regressions and say we are looking at the average change in the $y$ variable for a change in an $x$ variable, holding all other variables constant, what values are we holding the ...
4
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2answers
68 views

How can I calculate the effect of my equipment on my sport's performance?

I'm doing a stationary sport like golf, so the details matter. I'm recording each of my scores with detailed information about the equipment I'm using, and the weather conditions. So 1 score has 2-3 ...
3
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2answers
225 views

How are partial regression slopes calculated in multiple regression?

I'm trying to understand how multiple regression statistically controls for the effects of other predictor variables when calculating partial regression slopes. In a multiple regression of Y~X1+X2, ...
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0answers
48 views

Unexpected correlation, Method to account for the shared variance

Summary: While looking at the correlations I noticed a wired, relation. Variables: User comments - A; User community activity- B; Comments on user's wall - C (control) I expected that A and B will ...
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1answer
2k views

Covariates considered moderator or control variables?

Are covariates considered moderator variables or control variables? To elaborate on my question, I'm conducting a research study which has: variables that are supposed to affect the dependent ...
2
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1answer
150 views

Pros and cons of controlling for age when examining effect of cognition on driving performance

I am reviewing some studies on the relationship between cognition and driving. Some studies have controlled for age and some have not (age is correlated with cognition. Can anyone please provide any ...
2
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1answer
154 views

How to control for a variable

The goal of the analysis is to find a correlation between birth context and stature, while controlling for age. Each person has an ID number, age, stature, and birth context. That last part is what ...
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0answers
94 views

Too many controls?

I am purposely keeping this question vague since this has happened to me with multiple datasets. I have a DV and a few IV then several controls, and all looks fine. Then I add one more controls and ...
0
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1answer
145 views

Partial correlation

I want to create a regression model to predict state crime rate. There are two variables among 10 ( Vi= # of violent crimes per 100,000 population, Vi2 = # of violent crimes per 10,000 population) ...
0
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2answers
52 views

How to determine influence of two time series with feedback?

Say you have two time series, A & B. Each have a mutual effect on the other. To give a real-world example, say that time series A measures an artist's CD sales per month, and time series B is some ...
1
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1answer
133 views

Dividing controls between two groups of cases

I have a set of data that contains cases and controls. I would like to divide the cases by a particular phenotype before running my tests, to see how these groups differ (but not necessarily to ...
1
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1answer
442 views

What if only control variables are significant in a differences-in-differences analysis?

Regarding the standard DID model: $$ y=\alpha+\beta_1\text{treat}+\beta_2\text{post}+\beta_3\text{treatâ‹…post}+u $$ What exactly does it mean if say $\beta_3$ is not statistically significant, but ...
8
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3answers
136 views

What is the link between methods such as matching and statistically controlling for variables?

Often in research articles you read the researchers have controlled for certain variables. This can be done by methods such as matching, blocking, etc. But I always thought controlling for variables ...
0
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1answer
162 views

controlling for a highly correlated variable

In a paper looking at hand movements and time taken to complete a task it appears that the ratio of movements over time is constant (i.e., movement and time are highly correlated) yet they say in the ...
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3answers
1k views

How to control for market return in an (SPSS) OLS?

Please consider the following panel dataset: ...
1
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1answer
258 views

Interpreting Omitted Variables

I do not fully understand how to interpret the difference between two statistical models where they only differ based on whether a certain variable is included on the right hand side. If the results ...