USR company determined that on annual basis the company will monitor the manufacturing process of the phones made by the company. They decided to take a sample of the phones manufactured and check if the factory is making minimum defective units in the process. The standard deviation of the population is 15 units. The mean of the sample is 1750 units a) What proportion of phones can be expected to be defective if number of phones manufactured is between 1730to 1783 phones? b) What percentage of cars can be expected to travel either below 1720 or above 1750 thousand kilometers in the year c) What is the probability if the phones manufactured is less than 1768 or more than 1830? d) How many phones will be manufactured if the probability of defectives is at least 75% of the phones? e) What is the probability if the number of phones manufactured is more then 1734?