State budgets. States that rely on sales tax for revenue to fund education, public safety, and other programs often end up with budget surpluses during economic growth pe­riods (when people spend more

on consumer goods) and budget deficits during recessions (when people spend less on consumer goods). Fifty-one small retailers in a state with a growing economy were recently sampled. The sam­ple showed a mean increase of $2350 in additional sales tax revenue collected per retailer compared to the previous quarter. The sample standard deviation = $425.

 

a) Find a 95% confidence interval for the mean increase in sales tax revenue.

b) What assumptions have you made in this inference? Do you think the appropriate conditions have been satisfied?

c) Explain what your interval means and provide an exam­ple of what it does not mean.

In primary succession, over time, biomass tends to (pick the correct term from the two) decrease/increase; species tend to be shorter-lived/longer-lived; and species diversity tends to decrease/increase.

Succession can be defined as a series of ____of community members at a given location until a relatively ____ is reached.

Succession at Mount St. Helens revealed the importance of biological legacies, meaning living things or products of living things that ____.

In the interaction known as ____, one species feeds on all or parts of a second organism; in the interaction known as ____, a predator feeds on prey but does not kill it immediately and may not ever kill it.

In predator-prey interactions, ____ mimicry has occurred when one species has evolved to resemble another species that has superior protective ability. When several species that have protective ability have evolved to resemble each other ____ mimicry has occurred.

Mutualism is an interaction between individuals of two species that is ____. Commensalism is an interaction between individuals of two species in which one is ____while the other is ____.

The competitive exclusion principle states that when two populations compete for the same ____, one will always out-compete the other and thus bring about the latter’s ____.

Habitat often is shared within a community by means of____, defined as a dividing up of scarce resources among species that have similar requirements.

A keystone species can be defined as any species whose ____ a community would bring about significant change in it.

There are three principal types of biodiversity: ____, ____, and ____.