SOLUTION: What is lowest passing grade of 300 students, if the lowest 10% of the students are given a failing grade. Calculate the lowest passing score with the mean of 80, and standard devi

Question 970038: What is lowest passing grade of 300 students, if the lowest 10% of the students are given a failing grade. Calculate the lowest passing score with the mean of 80, and standard deviation of 10
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
The lowest 10% on the normal distribution is at z=-1.28
-1.28= (score-mean)/sd
-1.28= (score-80)/10
multiply by 10 both sides
-12.8=score -80
add 80 to both sides
score=67.2
if no decimals, 68 would not quite include the lowest 10%, and 67 would include a little more than 10%.
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