Class 15:  HIV Vaccines




Read the article “AIDS vaccine promising; experts urge caution” from the San Francisco Chronicle. 


1)    The article says that the vaccine was “31% effective in preventing HIV protection in comparison with placebo”.  What does this mean?  Where did the 31% figure from?

2)    What does it mean that half the participants given placebos?   Why was this done?  If the control group had not been given placebos, how do you think this would have affected the results of the trial?

3)     If the vaccine makes no difference, how many of the 125 cases of new HIV infection would you expect in the vaccine group and how many in the placebo group? 

4)    If you flip a coin 125 times, what is the chance that you get exactly 74 heads?  What is the chance that you get at least 74 heads / how would you figure this out?  What does this have to do with the HIV vaccine trial? 



Journal Assignment:


Read the list of project ideas and write down at least two project ideas that you would be interested in doing.  The ideas do not have to come from the list. 


Homework Assignment for Tues, Oct 20: 

On blackboard



Since I cancelled the birthday problem journal assignment, there have been only 3 journal assignments so far:  1) Car and Goats, 2) Drug testing, 3) Final project ideas.   Please hand these in on Tuesday.