Week 7: Logistic Regression and Odds Ratio

Question 1

How do you perform a cross-tabulation with chi-square?

Answer 1

<tab var1 var2, col chi2>

Question 2

How do you perform a logistic regression?

Answer 2

<logistic outcome_variable explanatory_variable(s)>
Remember categorical variables need to be proceeded with ‘i.’ accordingly <i.cat_var></i.cat_var>

Question 3

How do you calculate odds ratios directly in Stata?

Answer 3

<tabodds var1 var2, or>

Question 4

How do you modify existing labels on a variable?

Answer 4

Example:
<label define var_name 0”No”, modify>
<label></label>

Question 5

How do you formally interpret ORs?

Answer 5

Example:
Being female is associated with a 30% increase in the odds of asthma controlling for age (OR 1.30, 95% CI 1.01, 1.66). The odds of females having asthma are 1.30 times as much as the odds of males having asthma controlling for age.