Answer:
I. 60%
II. 75.4 kg
Step-by-step explanation:
We will use the z-scores and the standard normal distribution to answer this questions.
We have a normal distribution with mean 69 kg and variance 25 kg^2 (therefore, standard deviation of 5 kg).
I. What percentage of adult male in Boston weigh more than 72 kg?
We calculate the z-score for 72 kg and then calculate the associated probability:
II. What must an adult male weigh in order to be among the heaviest 10% of the population?
We have to calculate tha z-score that satisfies:
This happens for z=1.28 (see attachment).
Then, we can calculate the weight using this transformation:
