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
Research anesthetize and tag 37 adult female polar bears, measure their weight, and fit them with radio tracking devices. The following year, they are able to anesthetize and reweigh 32 of the bears. The average change in weight is -34.5 pounds with a standard deviation of 21.4. Does this indicate a significant drop in weight for the population?
Problem 2
A sample of 90 Eucalyptus trees is selected at random in Pacific Grove, California and
the number monarch butterfly (Danus plexippus) egg masses found on each tree is counted.
The average of these counts is 7.6. A very large survey the previous year found an average
of 6.8 egg masses per tree with a standard deviation of 2.1. Does the new data suggest that the average number of egg masses per tree is significantly higher this year than last?
Problem 3
Two contractors provides training in job search skills for unemployed workers. A sample of 43 workers trained by contractor A finds that 25 found jobs within 3 months of completing the training, while 18 out of 37 trained by contractor B found jobs within 3 months. Test the claim that the two contractors are equally effective if the measure of success is the number of trainees who find work within 3 months.