If there were 500 students in Jamal's class,approximately how many actual students scored higher than Jamal on the quiz if Jamal had a z-score of -1?
A)250
B)340
C)420
D)490

Question

Quizplus · Accepted Answer

To find out how many students scored higher than Jamal, we need to convert his z-score to a percentile. Using a standard normal distribution table, we can see that a z-score of 1.30 corresponds to a percentile of approximately 90.31%. This means that Jamal scored higher than approximately 90.31% of the class, leaving approximately 100% - 90.31% = 9.69% of the class who scored higher than him. To find the actual number of students, we can multiply 9.69% by the total number of students: 0.0969 x 500 = 48.45. Since we can't have a fractional part of a student, we round up to the nearest whole number, giving us an answer of approximately 49. However, we need to remember that this is an estimate, so the closest answer choice is C, which gives an estimate of 420 students scoring higher than Jamal.

If There Were 500 Students in Jamal's Class,approximately How Many