# Which statistical test

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#1
I have two data sets: they pertain to the same thing except one is before and the other after an intervention

I am seeing what percentage of patients with a shoulder dislocation where seen within 1hr after admission. Before my intervention 4/56 were seen within 1hr. After it, 3/10 (a different sample of patients all together) were. Which statistical test can I use to see if there is a significant improvement?
NOTE the groups of 100 are NOT related

Can I use chi square. If not what
(or should I use the Fisher Exact as the second population size is very small)
Thanks
0
2 years ago
#2
I think you'd use a paired t-test as you are comparing linked data sets.

Please wait for someone else to confirm this though as it's been a good few years since I've done any statistics.
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#3
I think you'd use a paired t-test as you are comparing linked data sets.

Please wait for someone else to confirm this though as it's been a good few years since I've done any statistics.
So the data sets are not linked
I tried the paired t-test but the results for each patient is binary: Yes or No (0 or 1)
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2 years ago
#4
(Original post by jsmith6131)
I have two data sets: they pertain to the same thing except one is before and the other after an intervention

I am seeing what percentage of patients with a shoulder dislocation where seen within 1hr after admission. Before my intervention 4/56 were seen within 1hr. After it, 3/10 (a different sample of patients all together) were. Which statistical test can I use to see if there is a significant improvement?
NOTE the groups of 100 are NOT related

Can I use chi square. If not what
(or should I use the Fisher Exact as the second population size is very small)
Thanks
You want a test for the "difference of proportions". In "R" you can do this with the function "prop.test".
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#5
(Original post by Gregorius)
You want a test for the "difference of proportions". In "R" you can do this with the function "prop.test".
If I write it up, what is this called scientifically
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2 years ago
#6
(Original post by jsmith6131)
If I write it up, what is this called scientifically
Difference of proportions test.
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#7
(Original post by Gregorius)
Difference of proportions test.
Thanks. So this is the same as chi-square then?
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