The logistic regression is given by –
πi=Pr(Yi=1|Xi=xi)=exp(β0+β1xi)1+exp(β0+β1xi)
The coefficient formula for logistic regression, also known as the logistic function or sigmoid function, is as follows:
�(�=1∣�)=11+�−(�0+�1�1+�2�2+…+����)P(y=1∣x)=1+e−(β0+β1x1+β2x2+…+βnxn)1
Where:
- �(�=1∣�)P(y=1∣x) is the probability that the dependent variable �y equals 1 given the independent variables �1,�2,…,��x1,x2,…,xn.
- �0,�1,…,��β0,β1,…,βn are the coefficients or parameters of the logistic regression model, representing the relationship between the independent variables and the log-odds of the dependent variable.
- �e is the base of the natural logarithm.
This formula calculates the probability of a binary outcome (usually coded as 0 or 1) given the values of the independent variables. The logistic function ensures that the predicted probabilities lie between 0 and 1, making it suitable for binary classification problems.