Hypothesis Testing: Tips for time saving

Hi all,

I’ve noticed that if you have some concepts clear you might be able save many valuable seconds when answering this type of questions.

As an example, and far as I understand, the t-student critical value is always more conservative than the Z one. Which means that it will be more difficult to reject the Ho using a t-student critical value.

If within a question, the computed test statistic doesn’t fall within the rejection range of the Z’s critical value, I believe I can infer that will neither fall in the t-student critical value. It his accurate? Is this accurate regardless the sample size? If so, I could save some precious seconds if I see that the calculated test statistic doesn’t fall in Z’s range (I will have memorized the values) and I wouldn’t need to calculate the t-student critical range.

Do you know any other similar tricks that might allow to save some seconds?

Regards

They’ll give you part of a t-table for the degrees of freedom you need (plus a couple extra bracketing it to see if you can calculate degrees of freedom correctly!!!) Using the z-table is a reasonable approximation if you have d.f. >=30, but if I were setting the exam, I would give you something like d.f =20 and t-values for 18, 19, 20, 21 for various values of alpha.