Linked Questions
10 questions linked to/from The $z$-test vs the $\chi^2$-test for comparing the odds of catching a cold in 2 groups
44
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4
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What is the difference between McNemar's test and the chi-squared test, and how do you know when to use each?
I have tried reading up on different sources, but I am still not clear what test would be the appropriate in my case. There are three different questions I am asking about my dataset:
The subjects ...
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27
votes
4
answers
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Comparing and contrasting, p-values, significance levels and type I error
I was wondering if anybody could give a concise rundown as to the definitions and uses of p-values, significance level and type I error.
I understand that p-values are defined as "the probability of ...
- 1,505
16
votes
2
answers
19k
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Why use a z test rather than a t test with proportional data?
When testing the difference between 2 proportions why do we use a z-test rather than a t-test?
Further, is there a simple way to conduct an omnibus test for significant differences between more ...
- 265
22
votes
1
answer
5k
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At What Level is a $\chi^2$ test Mathematically Identical to a $z$-test of Proportions?
BACKGROUND: Skip safely - it's here for reference, and to legitimize the question.
The opening of this paper reads:
"Karl Pearson’s famous chi-square contingency test is derived from another ...
- 26.7k
10
votes
2
answers
4k
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Is the beta distribution really better than the normal distribution for testing the difference of two proportions?
I'm working at an online agency, where we run a lot of AB testing in order to test differences in proportion between two groups (test vs. control). Standard practice in the industry for testing ...
6
votes
1
answer
2k
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Interpretation of p-value in comparing proportions between two small groups in R
I wish to compare proportions between two small groups.
In group 1, 2 of 18 students received honours. In group 2, 9 of 21 received honours.
This is a small sample, so if I use the t-test:
...
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1
vote
1
answer
4k
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How to test for significance if groups differed at baseline?
I have a situation where I want to test for a statistically significant difference in the percentage of customers who own a product among two groups. The treated group gets a marketing message, and ...
- 21
2
votes
2
answers
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T Test or Chi Square?
There are 2 variables, City and No Of Matches won.
Variables:
1City
Sydney
Canberra
2No Of Matches Won?
Sydney: 200 out of 300
Canberra: 210 out of 300
Question: Is team Canberra ...
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1
vote
1
answer
328
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$\chi^2$ test of significance vs. goodness of fit
I have 644 companies out of which 154 went bankrupt. I investigate below if the bankruptcy is related to the sector type:
...
- 768
0
votes
1
answer
545
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effect size for pairwise permutation
I am reading a paper that is using permutations to compare the means of two different treatment groups (a nutrition study, took minimum - maximum) that have low sample sizes, and so the groups are ...
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