Font Paragraph Styles 171 Editing Voic A grocer receives his vegetables from three suppliers A, B and C. History shows that 30% of his stock come from A 45% A computer virus is infecting the computers of employees at a large clothing manufacturer. It is established that 25%% of come from B and the rest come from C. History also shows that 4%% of stock from A is substandard, 6%% of stock from B is computers are infected. The IT specialist randomly selects a sample of eight computers. substandard while 8% of stock from C is substandard. On a random check, the grocer selects a The probability that none of these 8 computers are infected is zucchini and finds it to be A. 0.347 substandard. What is the probability it came from C? B. 0.159 A 039 C 0.204 8. 0.458 D. 0.100 C 0 203 D. 0.407 12 (4 Marks) 9 [4 Marks) The probability that at most 2 of these & computers are infected is: Questions 9-10 refer to the problem below. A. 0.678 Employees arrive at their workstations at a particular company at an average rate of 3 employees B. 0.322 per minute. C 0.706 Assume the arrival times follow a Poisson distribution. D. 0.512 The probability that exactly 4 employees arriving in a 2-minute period B: 13 (4 Marks) A. D 341 Consider the normal distribution function. e area between z- scores of 1 52 and 2 78 is: B. 0.287 A. 0 933 C 0.168 B. 0.027 D. 0.134 C 0.0616 10 (4 Marks) D. 0.0843 The probability that at least 2 employees arrive in a 1-minute interval is: 14 (4 Marks) A. 0.734 Questions 14-15 refer to the problem below. B. 0.801 The lifetimes of a certain brand of pool pumps have an average span of 3 years with a standard deviation of C 0. 193 6 months. Assume these lifetimes are normally distributed. D. 0.929 What percentage of these pumps is expected to last between 2 and 3.5 years? A. 81.85% B. 13 59% C. 95.44% D. 78 19%