SOLUTION: The amount of time spent by adults playing sports per day is normally disturbuted with a mean of 4 hours and standard deviation 1.25 hours . a) Find the probability that a random

Algebra ->  Probability-and-statistics -> SOLUTION: The amount of time spent by adults playing sports per day is normally disturbuted with a mean of 4 hours and standard deviation 1.25 hours . a) Find the probability that a random      Log On


   



Question 918930: The amount of time spent by adults playing sports per day is normally disturbuted with a mean of 4 hours and standard deviation 1.25 hours .
a) Find the probability that a randomly selected adult plays sports for more than 5 hours per day .
b) Find the probability that if four adults are randomly selected, their average number of 5 hours per day .
c) Find the probability that if four adults are randomly selected , all four play sports for more than 5 hours per day .

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
mean of 4 hours and standard deviation 1.25 hours .
a) z=blue+%28x+-+mu%29%2Fblue%28sigma%29 z(5) = 1/1.25 = .8,
P(z > .8) = normalcdf(.8,100) = .2119 0r 21.19%
.........
b) n = 4, z+=blue+%28x+-+mu%29%2Fblue%28sigma%2Fsqrt%28n%29%29
z(4.95) = -.05/.625 = -.08 and z(5.05) = .08
P(x=5) = P(z < .08) - P(z < .08)
P(x=5) = 53.19 - 46.81 = 6.38%
....
c) select 4
P(all four play > 5hr) = (.2119)^4