Respuesta :
C. because you may only have one manipulated variable to be able to know the responding variable.
The right answer is C
Univariate analyzes make it possible to specify the relationship between two variables:
is the blood pressure (variable 1) different according to sex (variable 2)?
Is the proportion of smokers different according to the color of the eyes? etc.
The goal of univariate analyzes is to answer the question: is the difference observed between my patients a real difference or is it due to chance?
Univariate analyzes are based on statistical tests, to obtain a p-value (which is the probability that the observed difference is due to chance)