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 the prevalence of entomophthoralean fungus (Entomophaga maimaiga). A simple random sample of 125 quarter-acre plots is tested and 32 are found
to contain detectable quantities of the fungus. Find 99 and 95 percent confidence intervals
for the proportion of quarter-acre plots that contain detectable quantities of the fungus.
Problem 2
A sample of 85 deer ticks (Ixodes scapularis) from Long Island contains 12 that test positive for the Ehrlichia chaffeensis bacteria.
A sample of 120 deer ticks collected on Cape Cod contains 14 that test positive. Does the
sample evidence support the claim that the level of Ehrlichia chaffeensis infection at the collection sites is identical?
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 75 specimens from the dumping area showed titanimum levels of 12.3 parts per million
with a standard deviation of 5.1, while a sample of 68 specimens from a site 20 miles away
had an average concentration of 8.6 parts per million with a standard deviation of 4.2. Determine
whether this data supports the agency's assertion.