QUESTION 2

1. There are approximately one billionsmartphoneusers in the world today. In the United States the ages 13 to 55+ ofsmartphoneusers approximately follow a normal distribution with approximate mean and standard deviation of 36.9 years and 13.9 years, respectively.
2. Usehttp://onlinestatbook.com/2/calculators/normal_dist.html,http://onlinestatbook.com/2/calculators/inverse_normal_dist.htmlor Excel.
3. A) Determine the probability that a randomsmartphoneuser in the age range 13 to 55+ is between 23 and 64.7 years old. (round to 2 decimal places)
4. B) Determine the probability that a randomly selectedsmartphoneuser in the age range 13 to 55+ is at most 50.8 years old.(round to 2 decimal places)
5. C) Find the 80th percentile to one decimal place of this distribution.
6. D) Find the 30th percentile to 1 decimal place.
7. E) What is the probability that the age of a randomly selectedsmartphoneuser in the range 13 to 55+ is less than 27 years old. (2 decimal places)