The same wax will be used to make each candle, and it costs of a penny per cubic centimeter. Write polynomial functions to show
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Answer:
P(X<118.81)=0.0803
Step-by-step explanation:
Assuming the distribution for the mean life is approximately normal, with mean 120 months and variance 64 months^2, we can calculate the parameters for a sampling distribution with sample size = 89 computers.
The sampling distribution mean will be equal to the mean for a single computer:
The standard deviation will be adjusted by the sample size as:
With these parameters, we can calculate the z-score for X=118.81.
Then, the probability that the mean of a sample of 89 computers is less than 118.81 months is: