# 1-sided or 2-sided for excercise question

Hey guys,

I'm still confusing about using 1-sided or 2-sided in the excercise question.

I suppose the H0 is that the Extreme Ajax+ makes no difference, so hypothesized diff = 0 as shown in the solution.

So why can't we use 2-sided test in this case?

I may need some explaination here.

Thank you!

best,

Chun

1 answers ( 0 marked as helpful)

Two sided (two tailed) test is used

when the null contains an equality or an inequality sign

One sided (one tailed) test is used

when the null contains greater than,less than, greater than and equal to or less than and equal to sign

And here our hypothesis is

H0: μExtremeAjax+ - μAjax ≤ 0

H1: μExtremeAjax+ - μAjax > 0