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How to analyze this data?

mermaidrunner

New member
Feb 1, 2014
4
I gathered some data on kids who were screened for a disorder using two screening tools. Each child was screened using both tools. I wanted to see if one tool referred more kids for further testing than the other. I need to determine if there is a significant difference between the number of referrals of the two tools. Tool A referred 34 kids and tool B referred 16 kids. Best way to analyze in SPSS?
 

Yankel

Active member
Jan 27, 2012
398
If I get you right, for each kid you have two samples, one for each tool. Both numbers are continuous and you want to compare the tools ? If so, paired t test
 

mermaidrunner

New member
Feb 1, 2014
4
If I get you right, for each kid you have two samples, one for each tool. Both numbers are continuous and you want to compare the tools ? If so, paired t test
Yes, that is correct. Each kid has a result from each tool. There were 51 total kids tested. My main concern is that these screening tools aren't scored on a numerical scale. It is strictly pass or fail - is that going to have an impact on using the paired t test? Should I be looking at something more nonparametrical?
 

Klaas van Aarsen

MHB Seeker
Staff member
Mar 5, 2012
8,780
Yes, that is correct. Each kid has a result from each tool. There were 51 total kids tested. My main concern is that these screening tools aren't scored on a numerical scale. It is strictly pass or fail - is that going to have an impact on using the paired t test? Should I be looking at something more nonparametrical?
Hi mermaidrunner. Welcome to MHB!

That sounds like a two-proportion z-test, pooled for $H_0\colon p_1=p_2$.

See for instance this wiki page.
 

Yankel

Active member
Jan 27, 2012
398
Oh, it ain't numerical....you still have this problem that you get pairs, 2 samples for each kid, meaning you have correlation between these samples.

What about the McNemar's test ?
 

mermaidrunner

New member
Feb 1, 2014
4
Hi mermaidrunner. Welcome to MHB!

That sounds like a two-proportion z-test, pooled for $H_0\colon p_1=p_2$.

See for instance this wiki page.
I had some trouble setting up Mcnemars in spss.. it wasn't looking right . Any suggestions?

I actually went ahead and ran the 2 proportion z-test (in Minitab). Is that going to be effective? Just trying to cover all my bases before submitting.
 

Yankel

Active member
Jan 27, 2012
398
I think that the two proportion Z test is not suitable here, you have correlation within kids.

Here is a youtube clips showing how to do McNemar's test on SPSS.

McNemar Test - SPSS (part 1) - YouTube

Minitab doesn't support it, but you can download a macro from their website which does it.
 

mermaidrunner

New member
Feb 1, 2014
4
Can anyone spare a few minutes (with SPSS) and look over some analyses I ran related to this? Sorry, I'm out of the stats loop and need these for a project...