# bias

1. ### [ self-selection - nonresponse bias] 65% of population answered survey

Dear TalkStatstters, I want to investigate possible wage gaps between different groups of people with doctorate degree, in my region. So, I have in mind a regression where the dependent variable is the log of the ratio between two average wages. I have administrative data from the whole...
2. ### Unbiased estimate of cross-product for unbiased vector

Let g be an unbiased estimate of a vector G. Can g be used to find an unbiased estimate of the cross product GG′ (where G' is the transpose of G)? I'm stuck because naively using gg′ is a biased estimator, with the (upwards) bias depending on the noise in g.
3. ### Omitted-variable bias in the constant of multiple regression under heteroskedasticity

Good morning, I would like to have some deeper information about omitted-variable bias. Here is the real model: Callback = Constant + b1*Race + b2*Quality + b3*Race*Quality where Race and Quality are dummies variables and Callback is a rate (between 0 and 1) If I regress this simple linear...
4. ### Is it possible to Reduce/Correct Bias through EM algorithm?

I am dealing with few overdispersed count models and using mixed Poisson distributions to deal with overdispsered data. I've used MLE technique to estimate the paramters, however ML estimates are lower biased. I am trying to correct the bias using advanced technquies. I have started to read...
5. ### simultaneous causality correction?

Hi Based on a data set I have to answer whether the use of tele-diagnosis and tele-evaluation by health professionals in Andalusia has a positive impact in their perception of the technology usefulness. I have the variables: dependent variable: useful -how useful is tele-diagnosis and...
6. ### Bootstrap bias

Good day forum, I'm using a bootstrap approach to get a better understanding of a sampling distribution. I've heard that the bootstrap approach introduces a specific bias into the results. Would anyone be so kind as to explain this to me, and how to compensate for this - or otherwise refer me...
7. ### Bootstrapping - Should/Can I add the bias to the sample median?

Dear All I'm trying to analyse a questionnaire with responses to questions ordered on a Likert Scale ( 1= Disagree strongly to 5 = Agree strongly). We are comparing question responses between two groups of students, one group (n-25) who saw a video, one group (n=35) who were given a...
8. ### personality psych)self-selected sample bias = smaller variability?

Context: online personality survey (BFI) for age 10~65 (http://www.colby.edu/psychology/labs/personality/publications/Soto_et_al_2011.pdf) Measure taken: the authors tried to control for possible self-selection bias in the sample by "by examining the variability of Big Five domains and facets in...