An analysis of the grades on the first test in history 101 revealed that they approximate a normal curve with a mean of 75 and a standard deviation of 8. the instructor wants to award the grade of a to the upper 10% of the test grades. to the nearest percent, what is the dividing point between an a and a b grade?
select one:
a. 80
b. 85
c. 90
d. 95

b. 85

Step-by-step explanation:

Average grade (μ) = 75

Standard deviation (σ) = 8

Assuming a normal distribution, the z-score corresponding to the upper 10% of the test grades is z = 1.28.

The minimum grade 'X' within the top 10% is given by:

Rounding to the nearest percent, the dividing point between an A and a B grade is 85.

pay attention in your classes and concentrate the best thing you can do to raise your test scores is to pay attention when you're supposed to be learning the material: in class!

take good notes.

do your homework.

use mnemonics and other tricks.

do practice tests.

note: the best i know.

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