Question

Age and Shoe Size

Age (years) Shoe Size
8 7
9 8
10 9
8 9
14 9
15 11
10 10
33 9
27 9.5
45 10.5
Oliver is doing a study on age and shoe size. He collects the following ages and shoe sizes. Is his data a function? Why or why not?

Answer 1

of course not because f(x) returns unique output while input are different

Answer 2

no his data is not a function,
for every element corresponding to set B , there should be a unique element A
for age 8 we have size 7 as well 9. for different ages we can have same size but not vice versa