Question

Parts A-D

A) To be eligible for further consideration, applicants for certain civil service positions must first pass a written qualifying examination on which a score of 85 or more must be obtained. In a recent examination, it was found that the scores were normally distributed with a mean of 65 points and a standard deviation of 10 points. Determine the percentage of applicants who passed the written qualifying examination.

________%

B)The scores on an economics examination are normally distributed with a mean of 72 and a standard deviation of 14. If the instructor assigns a grade of A to 13% of the class, what is the lowest score a student may have and still obtain an A?

_________

C)The speeds (in miles per hour) of motor vehicles on a certain stretch of Route 3A as clocked at a certain place along the highway are normally distributed with a mean of 69.6 mph and a standard deviation of 6.78 mph. What is the probability that a motor vehicle selected at random is traveling at the following speeds? (Round your answers to four decimal places.)

(1) more than 71 mph______


(2) less than 65 mph_______


(3) between 71 and 78 mph_______

D)Use the appropriate normal distribution to approximate the resulting binomial distribution.

A marksman's chance of hitting a target with each of his shots is 70%. (Assume the shots are independent of each other.) If he fires 50 shots, what is the probability of his hitting the target in each of the following situations? (Round your answers to four decimal places.)

(1) at least 38 times______


(2) fewer than 26 times_______


(3) between 30 and 38 times, inclusive_________

Answer 1