For each of the following situations, state a null hypothesis (H₀) and a nondirectional (two-tailed) alternative hypothesis (H₁).

a. A bank advertises that customers never have to wait more than 5 minutes in line at its branches. A researcher standing in line decides to test this advertisement.

b. The average life expectancy in this country is 78 years. A researcher wishes to see whether students, when asked how long they expect to live, give estimates different from the actual life expectancy.

c. The American Statistical Association publishes a monthly magazine sent to all of its members. Not too long ago, an article was written asking, “How many chocolate chips are there in a bag of Chips Ahoy cookies?” (Warner & Rutledge, 1999). Nabisco, the makers of these cookies, claim there are 1,000 chocolate chips in each bag. The authors of this article wish to test this claim.

d. An automobile company claims that their truck gets an average of 20 miles per gallon. A disgruntled group of truck buyers disputes this claim.

e. A company that makes batteries claims its batteries last an average of 25 hours of continuous use. A consumer group believes they have data that suggest the batteries last less than 25 hours.