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
Analysis of a sample of 45 deer ticks (Ixodes scapularis) from wooded area reveals the presence of the Ehrlichiosis pathogen (the Ehrlichia chaffeensis bacteria) in 17 ticks.
The CDC estimates that 18% of ticks carry the pathogen. Is the data consistent with this claim?
Problem 2
In a double-blind study of Major Depressive Disorder (MDD), 43 subjects are evaluated using the Beck Depression Inventory (BDI). Subjects then receive drug therapy with seratonin-reuptake inhibitors (SRIs). After 8 weeks of treatment, subjects are reevaluated with the BDI.
The average difference in the before and after scaled BDI scores is -1.7 with a standard
deviation of 0.8. Can we conclude that SRIs are effective in mitigating the MDD severity
as measured by the BDI?
Problem 3
Nationwide statistics for alchohol rehabilitation facilities show that after 4 weeks of
treatment, 37% of patients manage to remain abstinent for 6 weeks. Out of 42 patients released from a certain alchohol rehabilitation clinic, after 6 weeks only 12 remain abstinent. Can we
conclude statistically that this particular clinic does not perform as well as the national average?