Re: Hypothesis Test Problem

Hey jeff2222.

You don't have too many samples for a t-test. Using the normal approximation is valid since you have a lot of samples.

Can you show us how you calculated your test statistic? Are you using a paired t-test? (Are the relationships between each pair strong enough to consider a paired test?)

Re: Hypothesis Test Problem

Hey thanks for the response,

(standard deviation of FIM at discharge)/sqrt(total number of patients) = 0.7006

(mean of FIM at discharge - mean of FIM at admission) = 19.6108

19.6018/0.7006 = 28

For the t-test I used:

t = (mean of FIM at admission - mean of FIM at discharge)/ sqrt((SD1^2/203 + SD2^2/203))

(41.8 - 61.5)/ 0.883 = -22.2

The patients at discharge are the same patients at admission, so there should be a strong relationship.

I think I may understand what the problem is, I need to be calculating the mean differences between the tests. Is that correct?

Re: Hypothesis Test Problem

Are you using a paired t-test? You should probably switch to one if you are not already doing so.

Re: Hypothesis Test Problem

I wasn't. I now am. Thanks for your help.

For anyone else reading this, the method for the paired t-test is explained well here: https://www.youtube.com/watch?v=vB1OmEY5Rcw

And the matlab function ttest has options to be used for a paired t-test.