Biology and Environmental Science Piers on public beaches are usually supported by widely spread piles or pillars and can extend a thousand feet into the ocean. Many piers are extensions of...

Biology and Environmental Science Piers on public beaches are usually supported by widely spread piles or pillars and can extend a thousand feet into the ocean. Many piers are extensions of boardwalks, and visitors frequently fish or simply sightsee along these walkways. Longer piers tend to be more susceptible to wind and storm damage. Independent random samples of concrete and wooden piers on public beaches along the California and Florida coasts were obtained and the length (in feet) of each was recorded. Assume the underlying populations are normal, with equal variances. Is there any evidence to suggest that the population mean pier length in California is greater than the population mean pier length in Florida?

In case you missed it, the United Nations declared 2008 as the International Year of the Potato. Seriously, potatoes are a good source of carbohydrates, protein, fiber, and potassium. However, the amount of each element varies depending on where the potato is grown. Independent random samples of medium-sized potatoes from Russia and China were obtained, and the amount of potassium (in mg) was measured in each. The data are summarized in the following table.

Assume normality and equal population variances. Is there any evidence to suggest that the population mean potassium level is different for a medium-sized potato in Russia and China?