1a) A person with a hearing loss of 40 dB is considered to have moderate hearing impairment. Statistics shows that the age a person starts to have moderate hearing impairment follows a Normal Distribution with a mean of 61.5 years old with a standard deviation of 4.8 years. Note: You shall use relevant Statistics formula and Standard Normal Distribution table to work on Q1(a). (i) Find the age (to 2 decimal places) that 10% of the people have not suffered from moderate hearing impairment yet. (ii) 15 unrelated people participate in a health check exercise organised by a Community Club. Evaluate the probability that their mean age of starting to have moderate hearing impairment is at least 60 years old. Explain why the evaluation can be conducted