Question

Q1 Suppose the lengths of telephone calls from a normal distribution with a mean length of 8 0 minutes and a standard deviation of 2.5 minutes. The probability that a telephone call selected at random will last more than 15.5 minutes is most nearly: a. p = 0.9987 b. p = 0.0013 c. p = 0.26 d. p = 0.0026 ===================================================================

Q2 A manufacturer of car batteries claims that the life of his batteries is approximately normally distributed with a mean life of 7 years and a standard deviation equal to 2 year. What is the probability that a battery last between 1 and 13 years? a. p = 0.99 b. p = -0.9974 c. p = 0.9974 d. p =0.74 ===================================================================

Q3 A manufacturing engineer takes 20 samples from a manufacturing process to verify if the production complies with a quality standard. The probability of a product quality defect is 0.03. What is the probability of finding more than 18 of the samples with quality defects? a. 0.0 b. 0.77 c. 0.51 d. 0.34 ===================================================================

Q4 On average a certain intersection results in 6 traffic accidents per month. What is the probability that for any given month at the intersection at least one (1) accident will occur? a. 0.95 b. 0.25 c. 0.75 d. 0.9975

Answer 1