logistic regression Flashcards
DV in logistic regression is what type of variable
binary
baseline model predicts what
most common occurrence not what value we after
categorical variable is from the model which is
small number of possibel outcomes
values of logstic vs linear regression
logsitic = between 0 and 1
linear = infinity- negativr infinity
if linear regression y = 0 logstic will =
0.5
higher thann 0 in linear regression = in logsitic regression
greater than 0.5
in the form of a prediction if linear regression y> 0 logstic =
1
logsitic is non linear how to make it back to linear regression
use odds
although y value is 0 or 1 outcome variable output will be
probabaility between 0 and 1, output is a probaility not 0 or 1 but between them
when we build logistic regression model y will take value of 0 or 1 but outcome variable will be
continuos score/ probability between 1 or 0
output is
probability not or 1 but between them
create model using what set and evaluate on what set
training, testing
selecting a threshold of 0.5 predicts
most likley outcome
ROC helps us and what are its axis
pick threshold, TP rate or sensitivity on y axis, TN or specificity on x axis
ROC captures
all thresholds simultaneously