Suppose test scores on a certain exam follow a normal distribution with μ = 70. If...
Suppose test scores on a certain exam follow a normal distribution with μ = 70. If 8% of students scored above 80, what is the standard deviation of the distribution?
Homework Answers
Answer:
Given,
Mean μ = 70
x = 80
P(Z > z) = 0.08
from the standard normal distribution table,
P(Z > 1.41) = 0.08
So z = 1.41
we know,
z = (x - μ)/s
substitute known values
1.41 = (80 - 70)/s
s = 10/1.41
s = 7.09
Standard deviation = 7.09
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