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
Excavation of the part of an 1862 Civil War battlefield held by the Confederates yields 1,024 spent bullets, 721 of which can be identified as .58 caliber minie balls. A similar excavation of a Confederate position from an 1864 battle produces 423 spent bullets and 327 minie balls. Does
this evidence suggest that the proportion of Union armament using this type of ammunition was the same in both battles?
Problem 2
A sample of 45 documents designed to simulate prints is exposed to indirect sunlight
for 1,000 hours. An optical instrument measures the "blackness" of the ink on a scale of
zero to 50, with 50 indicating total absorbtion of all colors and 0 indicating
total reflection of all colors. The blackness index for each document is measured before
and after exposure. At the end of the experiment, the average change in the blackness index
is -4.5 with a standard deviation of 3.0. Does this data support the claim that indirect
sunlight fades documents of this type?
Problem 3
Records from banding stations indicate that in 2004, the average weight of a certain species
of bird is 17.3 grams with a standard deviation of 2.0. In 2005, 73 individuals from this
species are captured and their average weight is 19.1 grams. Is this data consistent with
the claim that the average weight in the population has not changed?