Hi Reeza, Sorry, coming back to this, now that i understand the different on the referential/ref, i have got a question on odd ratio... Say, i am trying to predict likelihood to buy ice cream (event =1 , non-event = 0) using logistic regression. I have only one variable "Gender" (2 value= Male/Female), so, the formula would be like this. logit(p)=β0+β1∗female Odd ratio for female with reference to male (A) = odd(female)/odd(male) Next, I added in "TodayWeather" (2 value = Sun/Rain). logit(p)=β0+β1∗female+β2*SUN Q1) Why the Odd ratio for A with reference to male change? Shouldn't my Odd ratio for female still the same as (A) above? Since it is still comparing female and male (ie the odd of female to buy ice cream if increase by one unit)? Q2) Say (A) above is < 1, is it possible that once i added "TodayWeather", the odd ratio become > 1? Why? Thank you again.
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