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?
z(20) = (20-30)/8 = -10/8 = -5/4
P(x < 20) = P(z < -5/4) = normalcdf(-100,-5/4) = 0.1056
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Use the same procedure on problems "b" and "c".
Cheers,
Stan H.
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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?