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- Forcing Unequal Variance T-test in Scripts

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Feb 2, 2016 11:42 AM
(4743 views)

The following script performs multiple t-tests on multiple Y columns using the Oneway platform.

As called in this script, the t-test assumes equal variance but I would like to force this script to perform this t-test assuming unequal variance.

Could you help figure out how to do that?

dt = Open ("File");

m = [];

For(i=8,i<=N Col (dt),i++,

ow = Oneway( Y( Column( i ) ), X( :Disease ), t Test( 1 ), invisible );

owr = Report (ow);

m = m || owr["t Test"][Number Col Box( 4 )][1];

);

New Table( "t-tests", New Column( "p", numeric, set values( m ) ) );

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It appear there is some confusion caused because the outline box for both the equal and unequal version of the ttest is called t-Test. However, if you change the direct reference from

m = m || owr["t Test"][Number Col Box( 4 )][1];

to

m = m || owr[Outline Box(1)][Number Col Box( 4 )][1];

you will get your correct output

Jim

2 REPLIES 2

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It appear there is some confusion caused because the outline box for both the equal and unequal version of the ttest is called t-Test. However, if you change the direct reference from

m = m || owr["t Test"][Number Col Box( 4 )][1];

to

m = m || owr[Outline Box(1)][Number Col Box( 4 )][1];

you will get your correct output

Jim

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Re: Forcing Unequal Variance T-test in Scripts

Hi Jim,

Thank you for your answer. It works perfectly.

Best regards,

Thierry