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### Who decided that p value should be less than 0.05 and why? [duplicate]

In many scientific fields, a p value less than 0.05 is considered significant, pointing to real difference in reality, whereas anything above it cannot be accepted (i.e. null hypothesis cannot be ...
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### What are some examples of anachronistic practices in statistics?

I am referring to practices that still maintain their presence, even though the problems (usually computational) they were designed to cope with have been mostly solved. For example, Yates' ...
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### Is the exact value of a 'p-value' meaningless?

I had a discussion with a statistician back in 2009 where he stated that the exact value of a p-value is irrelevant: the only thing that is important is whether it is significant or not. I.e. one ...
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### Is p=5.0% significant?

Today I was asked, whether a p-value of 0.05 (exactly) is considered significant (given alpha=5%) or not. I did not know the answer and Google turned up both answers: (a) the result is significant if ...
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### Number of trials required from a binomial distribution to get the desired odds

This question may have been asked before, but I couldn't find it. So, here goes. From about 3000 data points that can be characterized as "wins" or "losses" (binomial), it turns out that there are ...
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### Why is usually the acceptable probability of type 1 and type 2 errors different?

This question is raised by my supervisor and I don't know how to explain. Usually the accepted confident level is 0.95 which means that the probability of type 1 error is 5%. But the usually ...
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### Paired t-test to support increase in student reading scores from fall to spring

I did a pre-test, post-test method and I tried to perform a t-test to show how reading scores increased from fall to spring. I’m not sure if my numbers are accurate. What throws me off is the NULL ...
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### Clinical trials significance

I have been a studying high energy physics (HEP) for the last few years but I recently started working on a project in medical imaging. I have been a little surprised (not entirely I was aware that 95%...
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### What is significant?

There is a widespread notion that a p-value less than 0.05 is to be considered statistically significant, and above, not so. I understand that the "0.05" was an arbitrary number, albeit arbitrated by ...
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### Optimal approach to independence check

I want to see if a vendor is biased against one type of vehicle compared to another. I have two categories of vehicles: OWN and T/C. The vendor sells fuel to these vehicles. The process is as ...
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### how to apply bootstrapping in this case?

I have a small sample of marks obtained by a group of students and I would like to apply a binomial test to check if more than half of the size of the classroom has failed due to the application of a ...
What are the origins of the names and letters in these distributions: What is the origin of the name in chi-square distribution $\chi_k^2$? And the origin of $t$ in student's $t$-test? And naming \$...