The operating time of a machine manufactured by company A is arandom variable (Unit: years) with a standard distribution of N (5;3,25).
a. A person who has purchased this device has used it for 2 years,calculating the probability that he or she will use it for at least4 more years
b. The company warranty for 3 years. Calculate the percentage ofproducts that are warranted by the company
c. A person who buys 10 units of this company, calculated theprobability of having no more than 2 machines must be warranted inthese 10 machines.
d. Among 10,000 products of company A, the probability of having nomore than 800 of these 10,000 products must be covered by awarranty
