If you're like me, you probably didn't learn much about data and statistics when you were in school. There were bits and pieces sprinkled throughout my math textbooks, usually at the end of a chapter, and usually sections that teachers deemed skippable.
Not so anymore. Since just before my teaching career began, data and statistics have been getting a lot more attention in math curricula. One of the last courses I took for my bachelors degree was a stats class where I learned about box-and-whisker plots for the first time. When I started my internship a few months later, I discovered kids were learning about those plots in Pre-Algebra.
It makes sense when you think about it. We have data flying at us every day in the form of survey results, charts, and infographics. It's important to be able to interpret all that information with a critical eye.
Something getting particular emphasis is the idea of sampling methods and using a representative sample. Say you're doing a survey on career goals among the student body at your school. You're not just going to ask the kids in the advanced art class and call it good. Likewise, if you want to know the average height of teenagers, you're not just going to measure the basketball team.
I got to thinking about this in reference to writing. Specifically, getting critique and feedback. It kind of follows the examples above, plus the reverse. You want to be a little bit narrow (if you're looking for information relating to teenagers, including grandparents in your sample doesn't make sense), but also not too narrow.
What determines "narrowness" in this case? There are certain things any reader can point out for you—typos, grammatical errors, things that truly don't make sense. But for the more subjective "Does this work or not?" questions, you probably don't want to seek the opinion of someone who doesn't read or even like your genre. If such a person comes along and gives their opinion anyway, you should see if anything's valid, but don't get too carried away with it.
At the same time, you don't necessarily want all your feedback to come from people who only read exactly the kind of thing you write, who may even write very similarly to you. Like I've said before, my critique partners are great because even though we all write YA, their strengths and preferences vary enough from mine to push me out of my comfort zone and make me stretch.
Have you had a representative sample in your beta readers and critique partners? How did you get that perfect selection?