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
In an experiment to evaluate the effect of high temperature and humidity on stored films,
35 identical test films are stored in a climate-controlled environment while another 50 identical test films are exposed to ambient temperature and humidity. After one year,
the films are evaluated for loss of transparency using a scale that runs from 0 to 100,
100 indicating no measurable loss of transparency and 0 indicating complete loss of transparency.
The average measure for the climate-controlled films is 98.2 with a standard deviation of 0.3.
The average measure for the non climate-controlled films is 97.3 with a standard deviation of
0.5. Does this data indicate that climate control is effective in preserving transparency?
Problem 2
In 2004 a banding station captures and bands 48 members of a certain species of migratory birds and records an average weight of 32.1 grams. The following year, they capture 34 members of that species, none of which have been previously banded, and record an average weight of 30.9 grams.
Historical records indicate that the standard deviation of the weight of birds of this species is 2.1. Does this data support the claim that the population mean weight for this species is lower in the second year?
Problem 3
In a survey of 150 households relocated to temporary housing after hurricane Katrina,
118 indicate that they intend to return to the places they were living before the storm.
Compute a 99% confidence interval for the proportion of families that intend to return
to their homes.