Hello. I know some vanilla javascript but am new to jQuery. 

I am trying to select checked radio inputs and then select only the ones whose html I have given a data-attribute of correct answer like so:

1. data-answer="correctanswer"

My jQuery currently looks like this. 

1. var checkedbox = $("[type='radio']").attr(":checked") === true; 
2.  checkedbox.data( "answer" ) === correct answer;

I then want to do .length of the variable so I can see how many correct answers people have given in a quiz.