I am wondering why I get different results when using these 2 approaches to testing for a significant difference between two independent samples. I am also wondering which approach is more accurate and why.
#1 compare confidence intervals generated from svytab row obs ci se
I find that the confidence intervals overlap
#2
test for significant difference using the following t-test for independent samples:
value2-value1/ square root of (standard error of value 1 ^2 +standard error of value 2^2)
this formula gets me to a value of 2.12, significant at the 95% level
Again, why is there a difference and which approach is more correct?
Thanks!
Lacey Hartman
Senior Research Scientist
Health Economics Program
MN Department of Health
tel: 651-201-3556
fax: 651-201-5179
[email protected]
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