Homework help please??? STATISTICS

[njmitchel0]

I have several problems dealing with hypothesis,
h_o, h_a, and what not...

Couple questions that Im unclear about...

1. How do I determine whether a a hypothesis is a left or right tailed test? Is this determined with the h_o or h_a?

2. Rejecting or failing to reject a hypothesis... How do I know which one to choose...also does it matter if the test is right or left tailed?

3. How is a conclusion drawn?


Help is so very much appreciated!!!!!!

 

[iMacmatician]

It's been a while since I took stats, so I'm a bit hazy on things.

1. How do I determine whether a a hypothesis is a left or right tailed test? Is this determined with the h_o or h_a?

Yes.

For example, if you were testing whether a modification to a rocket would make the rocket go up higher, you'd use a right-tailed test since you're only interested in whether the modification improves the upward distance (in other words, to the right). H0 = modification makes no change to distance, HA = modification increases distance.

If you were testing drag, however, you would use a left-tailed test because a lower drag (numbers to the left) is better. H0 = modification makes no change to drag, HA = modification reduces drag.

2. Rejecting or failing to reject a hypothesis... How do I know which one to choose...also does it matter if the test is right or left tailed?

You fail to reject the hypothesis when the P-value is greater than your alpha value (usually .05). You reject the hypothesis when it is less than your alpha value. It doesn't matter which side the tail is on (at least with a calculator).

3. How is a conclusion drawn?

You analyze your results (reject / fail to reject etc.) and then answer your original H0/question.

 

[njmitchel0]

thanks alot man