Does anyone have the ability to calculate the P value if there were a couple of more positive covid blood tests in the intervention group.
... or a couple of more negative tests in the control group.
isn't the published p val very close to null effect already... what would it take to push it over?
Alex,
Here are my thoughts now that I've had a breather from work and a few minutes to really look at this.
First, I'm done toying with Ellis. I have long suspected that he is an IO operative; now I am sure he is. He has revealed himself. Whether self-directed or having a handler matters not. IO is IO (ironic b/c some people here think I am an IO stooge with my lack of acceptance of some conspiracy theories that fly around here as truth). So that side mission is out of the way.
Anyhow, the purpose of the study, as stated by the authors was to see if mask wearing reduced the incidence of covid as defined by presence of it in blood serum (or absence of presence).
Regression analysis is, at the end of day, correlational, not demonstrating causation. I know people that try to say otherwise, some of them knowledgeable, but they are fundamentally wrong. I am not alone in that conclusion. The best this study could have ever hoped to state, given regression analysis, is that mask wearing is
associated with reduced incidence of covid in blood serum.
The correct analysis would be something like ANOVA. You introduce the independent variable of mask wearing. You take a random sample of the population of mask wearers and a random sample from the control group (non-wearers) and you test for signs of covid exposure in the blood. Very simple. Run ANOVA on the results.
Why did they want to look at each town separately? Masks either work or they don't. Town of residence should not matter one bit. Actually, I can guess why they did that. They have all kinds of noise in the data, like how much mask wearing, how much social distancing. These are continuous variables, not binary, and they are trying to smooth that out by using regression analysis. I get it. Actually, one of the obvious flaws of the study is that they are trying to handle all of these different continuous variables fairly and, at the same time, having a causation result. Way too messy! To much uncertainty. Too much subjective defining!
If someone agrees and wants to pass me agreed upon population sizes (all mask wearers and then all non-mask wearers) and then figures that we all agree on for the outcome of blood tests, I'll run the ANOVA for you (or there's probably an online site for that - just plug in the number kind of thing). I think the results are not going to be statistically significant.
The problem I'm having is that what they did is not clear to me (hence why I ask for agreed upon figures).
They queried both control and experimental group for symptoms. Those who reported symptoms (in either group?) were then asked to sit for a blood test. The results being analyzed are of the blood tests of those who agreed to be tested. I believe that's it.
If the above is accurate, then regression is absolutely wrong and ANOVA is easy (or even confidence intervals).
The 7.62% and the 8.62% reporting symptoms are red herrings. It's just there for informational purposes (though Ellis appears to have followed the false scent). It's just telling us what they had to work with when requesting permission and agreement for a blood test. Otherwise, it means nothing. Nothing can be inferred from it and, in fairness, the authors are not asking us to infer anything from it nor inferring anything themselves.
The 10,952 figure (consenting to blood test) is a key figure for the analysis.
However, the authors then obscure the ability to assess the results by not telling us the split of the 10,952 between mask wearers and non-mask wearers. We need that split to perform ANOVA. If we had that split we could retro-engineer the the number in each group (mask/ no mask) that blood tested covid positive. Maybe that info is somewhere deeper in the write-up and maybe someone with more time could dig it out.
So, to be clear, there are three major distillations of the population (N). 1. masks v no masks 2. self-reported symptoms v no self reported symptoms 3. Consent to blood test and actually be tested --------> blood test positive v blood test negative
That should cut through the smoke and mirrors in the abstract.
Someone gets me the figures for the distillations and I will give back the P value for this experiment.