1.
Which hypothesis, the null or the alternative, is the status-quo
hypothesis?
2. A university economist conducted a study of elementary school
lunch menus. During the state-mandated testing period, school
lunches averaged 890 calories. The economist claimed that after the
testing period ended, the average caloric content of the school lunches
increased/dropped significantly. Set up the null and alternative
hypothesis to test the economist’s claim.
3. Suppose the mean GPA of all students graduating from a
particular university in 1975 was 2.40. The register plans to look at
records of graduating last year to see if the mean GPA has decreased.
Define notation and state the null and alternative hypothesis for this
investigation.
4. A random sample of 100 observations from a population with
standard deviation 58 yielded a sample mean of 111. Complete parts a
through c.
5. A final scores of games of a certain sport were compared against
the final point spreads established by oddsmakers. The difference
between the game outcome and point spread (called a point-spread
error) was calculated for 250 games. The mean and standard deviation
of the point-spread errors are = 1.7 and s = 13.1. Use this
information to test the hypothesis that the true mean point-spread
error for all games differs from 0. Conduct the test at α = 0.10 and
interpret the result.
6. If a hypothesis test were conducted using α = 0.025, for which
of the following p-values would the null hypothesis be rejected?
7. For the α and observed significance level (p-value) pair, indicate
whether the null hypothesis would be rejected.
α = 0.10, p-value = 0.001
8. In a test of the hypothesis H 0 :µ = 40 versus H a : µ ≠ 40, a sample
of n = 50 observations possessed mean = 40.7 and standard
deviation s = 3.8. Find the p-value for this test.