Context: a very basic level statistics package computer lab. A scatter plot is produced for one integer variable versus another integer variable. The students are asked why the points form a grid pattern. Students are 1st year undergrads.
Problem: I am struggling in my attempts to come up with a clear question, that allows the students to get to see (...by 'thinking'...) that the discrete plot positions are due to the variable's data type. Using terms like 'class of the variable' is currently unlikely to be in their vocabulary. Forming a question that does not obviously contain the answer evades my befuddled brain.