LP Test : If the student gets the question right, his or her estimated ability increases, and the next question will be harder. If the student gets the question wrong, his or her estimated ability decreases, and the next question will be easier (this do not happen for quiz).
LP Quiz : If student take a quiz, they can refer to a book & pass the quiz. Quiz questions will be of standard difficulties & not customized to students ability like LP test.
HENCE, student can score well for QUIZ because they can REFER TO BOOKS WHILE TAKING QUIZ. BUT, student cannot REFER TO BOOKS while taking LP Test, so a student can be good in quiz score but may not be for LP Test.