As reported by a recentsurvey, thefast-food restaurant with the bestdrive-through time had a mean time spent in thedrive-through of mu equals 63.8μ=63.8 seconds. Assuming drive-through times are normally distributed with σ=2.9 seconds.
What is the probability that a randomly selected car will get through the drive-through in less than 60.1 seconds?
The lengths of a particularanimal's pregnancies are approximately normallydistributed, with mean μ=268 days and standard deviation σ=20 days.
(a) What proportion of pregnancies lasts more than 283 days?
(b) What proportion of pregnancies lasts between 238 and 278 days?
(c) What is the probability that a randomly selected pregnancy lasts no more than 263 days?
(d) A"very preterm" baby is one whose gestation period is less than 223 days. Are very preterm babiesunusual?