MA145 Final Exam - Takehome Portion
For each of the problems below, use the MA145 technology guide to perform a statistical analysis.
You should justify your choice of method, including any assumptions made in the use of the method.
You should indicate whether a two-tailed, left-tailed, or right-tailed analysis is appropriate,
and, in hypothesis testing problems, state the null and alternative hypotheses.
If the problem does not specify a level of significance, you should choose one.
Problem 1
A researcher wishes to determine whether the presence of entomophthoralean fungus (Entomophaga maimaiga), indicates a reduced level of gypsy moth (Lymantria dispar) infestation.
Gypsy moth egg masses are counted in 43 quarter-acre plots where the fungus is detected, and
52 where it is not. The number of egg masses in plots where the fungus is detected has a
sample mean of 32.4 and a sample standard deviation of 12.1. In plots where no fungus is
detected, the sample mean is 43.1 with a sample standard deviation of 15.0. Does this
study support the claim that the fungus lowers the level of gypsy moth infestation?
Problem 2
In a certain state funding is available for suppression of deer tick (Ixodes scapularis) infestation in wooded areas near population centers if it is suspected that 10% or more of the tick population may carry the Ehrlichia chaffeensis bacteria.
A sample of 120 deer ticks collected near the housing development where a bilogist lives results in 9 positive tests. Can
the biologist use hypothesis testing to argue for funding in this area? If so, how would
it be set up?
Problem 3
A government agency is trying to build a case to support the assertion that ocean dumping of
titanium dioxide waste in the Baltimore Canyon is resulting in detectable increases in titanium in the deep sea scallop (Placopecten magellanicus) population in the dumping area.
A sample of 175 specimens from the dumping area showed titanimum levels of 13.2 parts per million
with a standard deviation of 8.1. Published data indicates that the body burden of titanium in specimens from unpolluted areas averages 6.8 parts per million. Does the data support the agency's claim?