# Please help me selecting a test for my study

#### kite6k

##### New Member
Hi,

I was wondering if you guys can provide some ideas on best test for my samples size, since I am not very stat savvy.

My project consist of 3 components on decreasing hospital readmission of pneumonia using these drugs
drug A, B, and C comparing with control group with none of these drugs from last year.

The sample size is kinda different between them.

drug A + drug B + drug C compare with control -->small sample size (20 patient)
drug A Only compare with control -->small sample size (20 patient)
drug B Only compare with control --->larger sample size (250patients)
drug C Only compare with control ---->moderate sample size (100 patients)

It would be great if you guys can help me with this complicated test of different groups.

Thanks alot!!

#### Karabiner

##### TS Contributor
You control group has n=10 or so?

Looks like 4 2x2 tables, with Chi² test or Fisher's exact test, respectively.
The comparisons with n=20 subjects will probably have very low statistical
power.

With kind regards

K.

#### kite6k

##### New Member
Thank you for the kind response! I had all my data and encounter a problem with disproportional sample size. My control data has about 200 pneumonia admissions receiving standard drug with 30 Readmissions, but the study group has about 250 pneumonia admissions with 20 Readmissions, but the number of patients in the study group receiving drug A is very small (used in about 20 admissions only, and not all these patients used drug A, so that cut down to like 10 readmissions who used drug A). Is there a way for way to make a comparison between control and my study group to determine whether drug A has an effect on readmission?

Thank you very much for the help!

#### Karabiner

##### TS Contributor
Still, 2x2 tables, with Chi² test or Fisher's exact test. Or what else do you want to know?

With 170/30 (controls) versus 10/10 (drug A), total sample size is 220, which is not dramatically bad.

With kind regards

K.

#### kite6k

##### New Member
Is this how I set up my table data for comparison for 2015 control group and 2016 study group?

Pneumonia ↓→ 2015 (2016)
# Readmission 21 (21)
ED admission visit 158 ( 239)
TOTAL # 179 ( 260)

Percentage of 12% ( 8.00% )
Readmission

As you can see above, 2016 study group has a total of 260 admissions and an overall of 8% of readmission compare to control group (12%). However, only about half of that 8% received drug A. It is hard for me to see how much of drug A having an effect on readmission since only half of those readmissions used drug A. Or am I just thinking over my head...sorry for the confusion as I am a little confused myself. Thank you!

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