Final answer:
It is not advisable to fill in missing quantitative variables with 0 as it can distort the data and lead to incorrect interpretations.
Step-by-step explanation:
When filling in missing quantitative variables, it is generally not recommended to use 0. This is because using 0 as a placeholder can distort the data and lead to incorrect interpretations. For example, if you have a data set representing the heights of students in a class, and you fill in the missing heights with 0, it will falsely lower the average height of the class. Instead, you can use techniques like mean imputation or regression analysis to estimate missing values based on the available data.