1. More hypotheses. Write the null and alternative hypotheses to test each of the following situations.
a) A business magazine article reports that, in 1990, 35% of CEOs had an MBA degree. Has the percentage changed?
b) Recently, 20% of cars of a certain model have needed costly transmission work after being driven between 50,000 and 100,000 miles. The car manufacturer hopes that the redesign of a transmission component has solved this problem.
c) A market researcher for a cola company decides to field test a new flavor soft drink, planning to market it only if he is sure that over 60% of the people like the flavor.
2. Deliveries. The clothing company in Exercise 21a looks at a sample of delivery reports. They test the hypoth- esis that 90% of the deliveries are on time against the alterna- tive that greater than 90% are on time and find a P-value of 0.22. Which of these conclusions is appropriate?
a) There's a 22% chance that 90% of the deliveries are on time.
b) There's a 78% chance that 90% of the deliveries are on time.
c) There's a 22% chance that the sample they drew shows the correct percentage of on-time deliveries
d) There's a 22% chance that natural sampling variation could produce a sample with an observed proportion of on-time deliveries such as the one they obtained if, in fact, 90% of deliveries are on time.