SOLUTION: the number of hours a week students devotes to study is normally distributed,with a mean of 30 hours and a standard deviation of 8 hours.
a. what percent of student will study les
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Question 742883: the number of hours a week students devotes to study is normally distributed,with a mean of 30 hours and a standard deviation of 8 hours.
a. what percent of student will study less than 20 hours?
b.what percent of students will study more than 35 hours?
c. out of a class of 200 students, how many will study between 25 and 35 hours?
Found 2 solutions by reviewermath, stanbon:
Answer by reviewermath(1029) (Show Source): You can put this solution on YOUR website!
a. P(X < 20) =
= P(Z < -1.25)
= 10.56%
b. P(X > 35) =
= P(Z > 0.625)
= 26.60%
c. P(25 < X < 35) =
= P(-0.625 < Z < 0.625)
= 1 - 2(0.2660)
= 46.8%
Answer: 46.8% of 200 = 93.6 ≈ students
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
the number of hours a week students devotes to study is normally distributed,with a mean of 30 hours and a standard deviation of 8 hours.
a. what percent of student will study less than 20 hours?
z(20) = (20-30)/8 = -10/8 = -5/4
P(x < 20) = P(z < -5/4) = normalcdf(-100,-5/4) = 0.1056
--------------------
Use the same procedure on problems "b" and "c".
Cheers,
Stan H.
===================
b.what percent of students will study more than 35 hours?
c. out of a class of 200 students, how many will study between 25 and 35 hours?
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