data analysis interpretation and causality confounding Flashcards
when should you be concerned about estimates?
with CI - if the CIs show a contradictory estimate
clinically - if the doctor could diagnose something else 95% of time
what do 95% CIs mean?
that 95% of the time the estimate lies within the confidence intervals
what is the p value?
the probability that the p value is at least as big as your assuming the coefficient is actually 0
what does a small p value mean?
zero-assumption is probably wrong and an effect is likely
what does a large p value mean?
a zero assumption is probably right and an effect is unlikely
what is R2?
how good a fit the model is - how well the points align to the line of best fit
what is S?
the deviation of the point
how would you carry out a statistical test?
observe, guess using model, test R2, S, CI and p value and assess using p value, R2 and CI
what is the use of causal inference?
understanding and identifying causal effects help us to understand changing care and improvements
what is association not?
causation
why is causation of infectious disease and cellular processes fairly simple?
bacteria + person = illness
relaxed myometrial cells + prostaglandin E2 = contracted myometrial cells
how are cellular processes used in clinical practice?
relaxed mymometrial cells + prostaglandin E2 = contracted myometrial cells - can be used to induce labour
the deterministic approach to causation is easy. How is it used in life?
it is appealing to toddlers and how they work but is actually inaccurate as association does not necessarily mean causation
what are the multiple causes of pre-term birth?
obesity, smoking, diabetes, alcohol, SGA, country of residence, bacterial vaginosis, iatrogenic etc
why does presentation of data matter?
the way you present and type of graph convinces public in different ways
how do we study how things work?
come up with an estimate of the counterfactual
how can we infer if a change has worked?
can look at different things with different exposures and work out if one variable has more of an effect however everyone is different and there are different environments
what is exchangeability?
when estimating the counterfactual the best way to do this is by finding groups that are comparable through randomisation in a population. This is a biased tool however as you rely on probability to balance out all of the different factors that make people different and therefore need enough numbers to account for the differences and balance them out
what is random sampling error?
it is the random error in out population estimates, that result from chance fluctuations in our sample profile - sample population will never be perfectly representative of a whole population