Yes the Student_Credithours is in first Normal Form
2ND Normal Form
No it is not in 2NF. we will split the table into three Tables i.e.
Student (StdId , StuName,age) PK stdid
Discipline ( Disciplineid, Disciplinename,totalCreditHr) PK Disciplineid
Student_Credithour (StdId, Disciplineid, EaranedCredithr) FK StdId, Disciplineid
Pls correct if i am wrong and for 3rd NF pls help me out pootle flump