I have a problem involving making a Hypothesis Test for a treatment being performed. The outcome is measured with a health rating FIM. There are 203 patients before treatment and 203 after treatment , each has a health measurement FIM. I found a sample mean of 41.8 before treatment with a variance of 58.5, and a sample mean of 61.5 after treatment with a variance of 99.7. I want to perform hypothesis testing on this. I made the null hypothesis that the average after the treatment was the same as the sample mean before the treatment (41.8). Was that wrong to do?
When finding the z-score of the result I got approx. 28, which I do not think is correct because of how high it is. From what I understand I have too many samples for a two sample t-test correct? But nonetheless when I perform that I get a score of approx. 22. Which I think may also be incorrect.
Any advice would help,