3
votes
0answers
100 views

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 ...
236
votes
148answers
125k views

Famous statistical quotations

What is your favorite statistical quote? This is community wiki, so please one quote per answer.
53
votes
9answers
3k views

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' ...
32
votes
2answers
5k views

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 ...
14
votes
3answers
697 views

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 ...
4
votes
2answers
3k views

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 ...
8
votes
1answer
1k views

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 ...
0
votes
3answers
520 views

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 ...
2
votes
3answers
117 views

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%...
3
votes
2answers
178 views

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 ...
3
votes
1answer
128 views

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 ...
1
vote
1answer
135 views

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 ...
-2
votes
1answer
56 views

Was it legit from ,05 or ,005? [closed]

Quick question. My brain shot circuited after all the new data. What was the sig that was legit: was it from ,05 or from ,005? I have sig = ,019 Can I use it or does it have to be smaller?