it can not be a function because functions only have ONE input to each output
Answer:
This was an observational study.
Step-by-step explanation:
Given is that parents of children completed a questionnaire on the child’s light exposure both at present and before the age of 2 years.
This was an observational study since there is no treatment or control group.
We know that treatment, control groups or treatment groups are not specific to randomized control experiments.
X+2 or x+2=y. X would be Luke’s age and if you add 2 years you would get Ellen’s age (y). Hope this helps.