标题: One tailed or Two tailed [打印本页] 作者: soverby 时间: 2011-7-13 16:01 标题: One tailed or Two tailed
This is sort of a newb question, but when they are asking us to test if X is significantly different from Y blah blah we are supposed to use two tailed, and if they ask us to do a confidence interval like X +- (t value)(Standard error) , we use two tailed also.
We use one tail for F stat only?
I know you use one tail when you are testing if something is greater than or less than, and two tailed to test if it's equal to something.作者: zhaoyp 时间: 2011-7-13 16:01
I'd like to ask 1 also. I understand that for 2-tailed test, the rejection regions are at the 2 tails. For one-tailed t-test, let's say null is b1<=5, then where is the rejection region, in the positive side or negative side? Thanks.作者: RMontgomery 时间: 2011-7-13 16:01
freakingout...
here you would have
H0: b1 <= 5
Ha: b1 > 5
you would accept it if b1 <= 5... right.
so your rejection region is to the right... Look at the Alt to determine your rejection / acceptance region.
Two tailed:
H0: b1 = 5
H1: B1 <> 5
same thing => at the extremes are the rejection region.
