Question 1058647
A research concludes that the number of hours of exercise per week for adults is normally distributed with a mean of 3.5 hours and a standard deviation of 3 hours. Show all work. Just the answer, without supporting work, will receive no credit.
(a) Find the 80th percentile for the distribution of exercise time per week. (round the answer to 2 decimal places)
sample mean:: 3.5
ME = 1.282*3 = 3.845
80% CI:: 3.5-3.845 < u < 3.5+3.845
80% CI: -0.345 < u < 7.345
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(b) What is the probability that a randomly selected adult has more than 7 hours of exercise per week? (round the answer to 4 decimal places) 
z(7) = (7-3.5)/3 = 3.5/3 = 1.167
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P(x > 7) = P(z > 1.167) = normalcdf(1.167,100) = 0.1217
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Cheers,
Stan H.
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