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 manufacturer of pyrometric cones chooses a sample of 75 from a large production run and
records the temperature at which they bend under identical firing conditions. The mean
temperature is 1009.4 degrees centigrade, with a standard deviation of 9.3. Test the claim that
the mean bending time for the production run is 1000 degrees.
Problem 2
A random sample of 85 federal income tax returns from a county indicates an average claim
of $412.50 in charitable contributions with a standard deviation of 51.5. A sample of 75 returns
from another county indicates has an average of $386.87 with a standard deviation of 65.7.
Does this data support the claim that the level of donation to charity is the same in both
counties?
Problem 3
In a survey 320 college students are selected at random. 142 students report that they
perform at least 2 hours per week of community service. Construct a 95% confidence interval
for the proportion of college students that volunteer at least 2 hours per week.