Answer:
a) probability of choosing the mean amount of sleep for adult as μ < 9 hours when it is μ = 8.5 hours is 0.4038
b) There is a 0.5962 probability of failing to choose that the mean amount of sleep for adult is μ < 9 hours when it is μ = 8.5 hours
Step-by-step explanation:
a) Interpret the value of the power
The power of an hypothesis is the probability of rejecting the null hypothesis when the alternative hypothesis is valid. It is a type 1 error
Power = 0.4038
From the hypothesis test,
the null hypothesis, μ = 8.5 hours
Alternative hypothesis, μ < 9 hours
Sine the power is the probability of rejecting the null hypothesis, it means that the probability of choosing the mean amount of sleep for adult as μ < 9 hours when it is μ = 8.5 hours is 0.4038
b)
Power + β = 1
β = 1 - Power
β = 1 - 0.4038
β = 0.5962
β, type 2 error, is the probability of not rejecting the null hypothesis even when it is false.
It means that there is a 0.5962 probability of failing to choose that the mean amount of sleep for adult is μ < 9 hours when it is μ = 8.5 hours