Linked Questions

-3 votes
1 answer

What is a good P value for statistical significance when conducting a Wilcoxon Rank Sum test? [duplicate]

Is a P value of 0.4 statistically significant for a Wilcoxon Rank Sum test?
Jamerson2's user avatar
1 vote
1 answer

Reason behind the choice of the 0.05 p-value threshold value [duplicate]

I just would like to understand the basis and rational why 0.05 is widely used as the accepted value to decide rare or unlikely. Is p-value threshold related with the confidence interval or +/- $2\...
mon's user avatar
  • 1,374
3 votes
0 answers

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 ...
Dvir Adler's user avatar
282 votes
153 answers

Famous statistical quotations

What is your favorite statistical quote? This is community wiki, so please one quote per answer.
57 votes
10 answers

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
3 answers

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 ...
Mark Ramotowski's user avatar
15 votes
3 answers

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 ...
BurninLeo's user avatar
  • 501
6 votes
2 answers

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 ...
bill_080's user avatar
  • 3,548
9 votes
1 answer

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 ...
user2230101's user avatar
0 votes
3 answers

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 ...
user34719's user avatar
2 votes
0 answers

Chi-square origin of the name

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 $...
user2925716's user avatar
2 votes
3 answers

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%...
user36288's user avatar
2 votes
1 answer

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 ...
Layla's user avatar
  • 611
3 votes
1 answer

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 ...
KHH's user avatar
  • 33
3 votes
2 answers

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 ...
Superbest's user avatar
  • 253

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