The observational-study tag has no wiki summary.
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A randomized, double-blind crossover (AB/BA) observational study of new use of an FDA approved drug
I found a new use of a drug already in use. The results are as follows.
Serail No. of Patient-- Attacks while on Placebo-- Attacks while on drug --Difference in the no. of attacks
1- 23- 2- ...
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60 views
Model vs observation, obtaining an optimal fit
This is a pretty general question regarding observations versus modelization and how to obtain the modeled set that best fits/reproduces an observed set of objects.
I have a given set made of ...
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43 views
Global warming testing
I'm very interested in weather. I use data from weather-stations.
Here are 2 examples of changing average annual temperature in Vienna and Moscow.
(I've got more, but only 2 links allowed ((
...
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129 views
R statistics: Adjusted Chi-squared test for clustered binary / categorical data
I'm looking for some assistance in statistical analysis with R, but also some general stats advice.
I am analysing cardiac phenotype data by comparing 2 groups. The 2 groups are unmatched ...
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1answer
103 views
Best way to use statistics to describe data from an observational study
I have followed two groups and measured a number of variables. Some of the variables can be used to calculate new measures. Is it ok to average the two groups and analyse calculations from the ...
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1answer
71 views
Stat analysis of seasons duration
Firstly, how we can define seasons - Winter, Spring, Summer and Autumn?
There are many possibilities, let's choose average twenty-four hours temperature $\bar t$.
Next we set $t_1$ and $t_2$ ...
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2answers
62 views
Is it fair to say that most epidemiological studies are observational?
Is it fair to say that observational studies are the 'bread and butter' of epidemiological studies?
By epidemiological studies I mean studies looking for an association between an environmental ...
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1answer
74 views
Identifying populations and samples from a dataset
I'm writing a proposal for a restrospective cohort study using registry data. Am I right to think of the registry data as the whole population?
If it is the population, then am I right in thinking ...
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1answer
417 views
How well can multiple regression really “control for” covariates?
We’re all familiar with observational studies that attempt to establish a causal link between a nonrandomized predictor X and an outcome by including every imaginable potential confounder in a ...
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1answer
270 views
Is Cox regression analysis including demographic covariates required for observational studies instead of Kaplan-Meier?
I have been reading quite a few papers and recently have started analyzing some data on a review that I am doing.
I am trying to examine the effect of two different treatment options on a group of ...
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1answer
79 views
How can the robustness of observational studies be increased?
In a very general sense, what are the different ways in which a retrospective observational study can be made to be robust?
Cross-validation?
Well-defined exposures?
etc.
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53 views
finding effects in online advertising data
So i have some online banner ad campaigns and sometime during the life of the each campaign i look at my data and come to the conclusion that some variable in a campaign: adsize, how often i show ...
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2answers
618 views
Power analysis for observational study of secondary data
I am involved in a project that is attempting to measure the impacts of person-level, county-level and medical service area-level predictors on individual probability of returning to a hospital within ...
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1answer
150 views
What statistical test should be used to accomplish the objectives of the experiment
I'd like to have your feedback to analyze my data from the following experiment.
Experiment Information
A total of 30 (15 from one city and other 15 from another city) slaughtered animals were ...
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45 views
Comparing questionnaires with actual observations: is it worth it?
First of 2 part query: I have observed a 100 Drs and recorded the number of times they touch surfaces while in a room:
$$
\begin{array}{l|c|c|c|c}
Dr\text{ ...
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3answers
190 views
Can a categorical variable be divided by a numerical variable?
I am reading P.R. Rosenbaum, Model-based direct adjustment, Journal of the American Statistical Association, 1987 (82), pp. 387-394. However, there is one equation, which I can't understand.
$$
d = ...
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1answer
346 views
How to test for and deal with regression toward the mean?
I am working with a large dataset of behavioral data that I am treating (post-hoc) as a time-series experimental design to look for reliable change in a single dependent variable as a result of a ...
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1answer
173 views
Inverse probability of treatment weighted (IPTW) estimator for a binary outcome
Recently, there are several estimators have been proposed to estimate the average treatment effect (ATE) in observation studies, such as IPTW, doubly-robust estimator, etc. It fully makes senses to me ...
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211 views
Whether to use structural equation modelling to analyse observational studies in psychology
I've noticed this issue coming up a lot in statistical consulting settings and i was keen to get your thoughts.
Context
I often speak to research students that have conducted a study approximately ...
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1answer
583 views
What does “case-control” and “cross-sectional” mean in the context of logistic modeling?
While studying logistic modeling, I read the following statement
The fact that only odds ratios, not individual risks, can be estimated from logistic
modeling in case-control or ...
