Odds Ratio??

[TwinkleK]

Hey,

I know the calculation for "odds ratio" is:
(A/B)
(C/D)

which is then rearranged to:
(AxD)
(BxC)

This is the question:
6) An epidemiological study is undertaken to examine the response of two groups of patients to a new drug
treatment. The results are summarised in the following data tables.

Patient group 1
---------- (Positive response)----(Adverse effects)
Treatment-------14 -----------------------28
Placebo----------- 9------------------------29

Patient group 2
----------(Positive response)----(Adverse effects)
Treatment------ 16----------------------- 32
Placebo-----------7 ----------------------- 45

"(a) Calculate the odds ratios for treatment for both of patient groups 1 and 2.

(b) Calculate odds ratio for treatment on aggregated data (i.e. both patient groups combined)"

For (a) I applied the formula and got "1" which seems right, because all the research done say's so lol.

For (b) I am stuck, because I don't understand how I would come about placing the numbers into the equation. I have done two equations and both of them I recieved okay numbers (i.e one number above 1 and one under 1) whih is expected but the mthod used is different. I just don't know what to do Can anyone please help?

Thanks in advance x

[TwinkleK]

Anyone?