Question

XI. USE THE INFORMATION BELOW TO ANSWER PROBLEMS 35-36 Suppose that long time data shows that patrons of coffee houses on average get coffee at 13.23 hours with a standard deviation of 3.46 hours (hours as measured on a 24-hour clock). The data is assumed to be approximately Normally distributed. You are interested in the probability in a random sample of 15 patrons the average time after which they get coffee is 14.25 hours. 35. Pick the equation that is most appropriate to deal with the problem above. a) b) Z c) 36. x = 20 d) p(x) = nCxp*(1 - p)*-* e) None of the above Find the probability that in a in a random sample of 15 patrons the average time after which they get coffee is 14.25 hours? Round to 2 decimals. a) 0.87 b) 0.13 c) 0.39 d) 0.61 e) None of the above

Answer 1

Given the distribution follows a normal with mean 13.23 and standard deviation 3.46and sample size n=15 35) Formula for z score is z = o/vn Option a is correct 36) Probability that average time after which they get coffee is 14.25 is P(>14.25 ) =P - lo/n 14.25-13.23 3.46/15 =P(21.14) =1-P(z<1.14) =1-0.8729 =0.1271 =0.13 (using z value table) Option b is correct