How to identify in a given problem whether it is One-tailed vs two-tailed (Or one-sided test vs two-sided)… and what are we supposed to use for the calculation (z-table, t-table)? Can someone please elaborate…
With known variance and a large sample, you’re better off using Z- Test. With unknown variance and small sample, T-Test. There is a chart somewhere in Qbank which I can no longer find. With regards to one or two tailed, I’m not sure and I wish i knew.
if it is H = 0 then it is 2-tailed because you can be either > or < if it is H > 0 or H < 0 then it is 1-tailed because you can only be on one side of it
normal/known variance: t (small) z (large) normal/unknown variance: t (small and large) nonnormal/known variance: n/a (small) z (large) nonnormal/unknown variance: n/a (small) t (large)
thanks all for your inputs… For this: if it is H = 0 then it is 2-tailed because you can be either > or < if it is H > 0 or H < 0 then it is 1-tailed because you can only be on one side of it … I am guessing the catch words are “greater than” or “less than”… if these are not mentioned, then it is 2-tailed test… Please clarify… thanks again…
2-tailed tests have catch-phrases such as “different from 2%”
that’s what i use, finfan. if it mentions greater than or less than, it’s a one tailed. if it mentions same as or equal to or something along those lines, then it’s a two tailed.
nirjraina Wrote: ------------------------------------------------------- > 2-tailed tests have catch-phrases such as > “different from 2%” Is it because it can mean anything less than or greater than 2%? Got to interpret the wording sooo much on these problems…
yup, you got it. think of a normal distribution chart and plot the 2% in the middle. if it’s “different” then it can go either way. more or less than 2%. (to the right or left) if it’s one tailed, it can only be one side of the 2%.
okie… got it… thank you soo much 