Salary at big4

What is the salary range in big4 companies for data scientists with 3.5 years of experience?

What sort of questions are asked in big4 for a data scientist role with 3.5 years of experience?

Hey Guys, I am a Data Engineer, working in analytics at a big 4 firm, with about 2yrs experience. Need a mentor to guide me, stuck in a job paying me below average salaries and I am quite unsure of what to do in my life. Please help.