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gtucke1
Fluorite | Level 6

I want to run two-tailed t-tests using the following code:

Title "Age and Dementia Education";
Proc ttest data = X sides = 2 alpha = 0.05 h0=0;
Class h1_unmet;
Var cg_age;
Run;

Is this the correct code?

 

I've seen both two-tailed t-test and two sample t-tests mentioned. Are they different? I yes, what is the difference. 

2 REPLIES 2
PGStats
Opal | Level 21

If h1_unmet takes two values, the statement Class h1_unmet; defines two samples. The option sides=2 requests a two-sided test, i.e. the cg_age difference will be significant if it falls on the extreme left tail or the extreme right tail of the T distribution.

PG
PaigeMiller
Diamond | Level 26

If you have a data set and you want to compare the mean to a specific value (usually zero, but other values are possible), this is a one sample t-test. The hypothesis you are testing is H0: Mean = k

 

If the data set has two groups (such as male and female), and you want to compare the mean of group 1 to the mean of group two, this is a two sample t-test. The hypothesis you are testing is H0: Mean 1 = Mean 2

 

Both of the above are two-sided tests, because either the mean > k or mean < k would be a violation of H0

 

If you want to test to see if the mean is greater than or equal to some value k (as opposed to the mean being equal to k), this is a one sided test. For the two sample case, the one sided test would be H0: Mean1 > Mean 2

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Paige Miller

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