A weak student is a sign of a dull teacher.
Only one quality required in a student is that he should be ready to learn but a teacher quality is have a sufficient knowledge about how to teach.
After learning a subject a student should be so capable that he must teach other student.
If student is able to teach other after learning a topic then he should change the teacher.
Because students are never weak in subject .
It's teacher who make a student a weak student or strong Student.
One to one tution helps you much because here only those things are taught which you are required but in group study your most of the is wasted because teacher has to teach according to all student's requirements.
So you have learn there those things also which you already know.
Online tution save your time which you spend in going to tution centre and coming back from there.