Jump to content

Beginning statistical analysis

Recommended Posts

I've got a question about how to do statistical analyses:


Let's say a randomized controlled study of the efficacy of a new antiretroviral agent to be used in treating HIV/AIDS --specifically, the one here: http://www.scienceforums.net/forum/showthread.php?t=32796 -- is commenced in HIV+ mice, w/ 20 mice randomly assigned to the treatment group, and 20 mice randomly assigned to the placebo group. 18 mice in the treatment group end up w/ viral loads < 50 copies/ml --which is definied in the literature as clinically insignificant--, and a CD4+ T-cell count of > 500 cells/ul, which is that of a healthy individual --the remaning two succumbed from causes unrelated to HIV--. Those in the placebo group, all died.


Now, what can I do with this data, or do I need more data? What data do I need to calclate the mean and standard deviation, so I can calculate the 99% CI --or the 1% p-value; any difference? What CL or p-value would be appropriate in this situation?-- and the effect size? Would the above RCT's results be statistically significant --they sure are clinically significant!--?



Link to post
Share on other sites

Because the trial contains mice that died of other causes, I would probably analyse this as a markov process and determine rates rather than probabilities. The rates can then be turned into probabilities


Probability of survival to time t = exp[-integrate between t and 0 mu(s) ds], where mu(t) is the death rate at time t


Maximum likelihood estmates of rates and the variances are probably easily calculated from exposure times and no of deaths

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.