- 6 The Lengths Of Pregnancies Of Orca Whales Are Normally Distributed With Mean Of 505 Days And A Standard Deviation Of 1 (90.23 KiB) Viewed 106 times
6. The lengths of pregnancies of orca whales are normally distributed with mean of 505 days and a standard deviation of 18 days. (10 points) a. What percentage of orca pregnancies last 535 days or longer? b. If we stipulate that a newborn orca is premature if the length of pregnancy is in the lowest 4%, find the length (gestation) that separates premature babies from those who are not premature. (5 points) (10 points) 7. A sample of 35 teens aged 15-18 years showed an average of 2.9 hours of cell phone use per day with a standard deviation of 0.5 hours. (15 points) a. Find a 90% confidence interval for a number of hours per day teens in this age group spend using cell phone. (10 points). b. If you increase the confidence level, will the confidence interval estimate be wider or (5 points) narrower? Explain.