Logistic Regression Flashcards
What type of dependent variable is used in logistic regression?
Binary categorical variables (dichotomous), such as success (1) or failure (0)
What is the primary goal of logistic regression?
To estimate the probability of a binary outcome given a set of predictor variables.
Write the logistic regression formula.
log( p/1−p)=β_0+β_1x, where 𝑝 is the probability of the outcome.
Why can’t we use linear regression for binary outcomes?
Linear regression can predict probabilities outside the range of 0 to 1, which is invalid for binary outcomes.
What is the null deviance in logistic regression?
It measures the goodness of fit of the simplest model (intercept-only model)
How does residual deviance differ from null deviance?
Residual deviance measures the goodness of fit of the full model; a lower residual deviance indicates better fit.
What is the AIC value in logistic regression used for?
Comparing models; a lower AIC indicates a better-fitting model.
In the example provided, what factors were associated with flu shot status?
Age and health awareness.
What does a significant p-value in the coefficients table indicate?
That the predictor variable has a statistically significant association with the outcome.
Why are odds ratios useful in logistic regression?
They interpret the effect size of predictors on the probability of the outcome.
What type of variable is typically coded as 1 or 0 in logistic regression?
Dichotomous variables like survived/did not survive.
What is the interpretation of a positive coefficient in logistic regression?
An increase in the predictor increases the log odds of the outcome.
What does the logistic regression output include that is not found in linear regression?
Log odds and probabilities.
What is the primary assumption of logistic regression regarding the relationship between the predictors and the log-odds?
It assumes a linear relationship.
Beyond the topic: How might logistic regression be applied to predict health outcomes in your community?
Free response
