Hi everyone! I'm new here, write from Italy so may you all accept my apologies for my english... hope to be understood anyway.
I am graduating in physiotherapy and doing an experimental study as thesis dissertation, a sort of little clinical trial. I'm writing here because i begun experiencing some difficulties with statistical analysis of the data I collected.
This is the experimental design: I recruited 30 subjects and randomized them into 3 groups: group 1, 2 and a control group.
Then I measured each subject's ankle range of motion (ROM, which is how many angular degrees a joint moves). Then, a 10 years experienced physio treated each subject according to the group they belong to. Then I measured ankle ROM again. I did not know how each subject was treated until all the experiments have been done, when I put together measurements and subjects' allocations.
To summarize, I now have 3 groups made of 10 subjects each. Group 1 and 2 received a treatment that we hypothesized should improve range of motion (and we wish to now which one is the more effective), group 3(control) received a placebo treatment which had no effect.
The analysis I made if, for each group, a paired two tailed student's t test to see if changes between pre- and post- treatment are statistically significant. Then I used unpaired two tailed Student's t test to compare groups' mean of the differences between pre- and post measurements. So, I made group 1 VS 2, 1 VS control, 2 vs control... reaching statistical significance in all of those comparisons (p<0.001).
BUT, reading some statistical tutorial n the net, I discovered that it is not correct to use Student's t test the way the way I did to compare groups!! I found out I should use an ANOVA.
Well, I finally come to the point. Can I use an ANOVA, to compare differences occured in subjects after they received the treatment? Or have I to use absolute values? Because, mean of the differences show that there is come substantial difference between each group, but the same don't do the absolute values given that ankle ROM is a value that differs much between various subjects.
Also, I would be advised how to carry out the ANOVA (software, spreadsheet, whatever?) or suggested if there is any other kind of statistical test or tool that better fits my needs.
In a few hours I will attach to this thread an excel spreadsheet with the measures I took... now I don't have them here with me.
Thank you!!
I am graduating in physiotherapy and doing an experimental study as thesis dissertation, a sort of little clinical trial. I'm writing here because i begun experiencing some difficulties with statistical analysis of the data I collected.
This is the experimental design: I recruited 30 subjects and randomized them into 3 groups: group 1, 2 and a control group.
Then I measured each subject's ankle range of motion (ROM, which is how many angular degrees a joint moves). Then, a 10 years experienced physio treated each subject according to the group they belong to. Then I measured ankle ROM again. I did not know how each subject was treated until all the experiments have been done, when I put together measurements and subjects' allocations.
To summarize, I now have 3 groups made of 10 subjects each. Group 1 and 2 received a treatment that we hypothesized should improve range of motion (and we wish to now which one is the more effective), group 3(control) received a placebo treatment which had no effect.
The analysis I made if, for each group, a paired two tailed student's t test to see if changes between pre- and post- treatment are statistically significant. Then I used unpaired two tailed Student's t test to compare groups' mean of the differences between pre- and post measurements. So, I made group 1 VS 2, 1 VS control, 2 vs control... reaching statistical significance in all of those comparisons (p<0.001).
BUT, reading some statistical tutorial n the net, I discovered that it is not correct to use Student's t test the way the way I did to compare groups!! I found out I should use an ANOVA.
Well, I finally come to the point. Can I use an ANOVA, to compare differences occured in subjects after they received the treatment? Or have I to use absolute values? Because, mean of the differences show that there is come substantial difference between each group, but the same don't do the absolute values given that ankle ROM is a value that differs much between various subjects.
Also, I would be advised how to carry out the ANOVA (software, spreadsheet, whatever?) or suggested if there is any other kind of statistical test or tool that better fits my needs.
In a few hours I will attach to this thread an excel spreadsheet with the measures I took... now I don't have them here with me.
Thank you!!
