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 a poll conducted four weeks prior to an election on a random sample of 400 likely voters in
a large city, 186 respondents indicate that they plan to vote yes on a certain ballot question.
Calculate a 99% confidence interval for the proportion of voters who plan to vote yes in the
population.
Problem 2
Samples of 75 pyrometric cones from two production batches are subject to identical firing
conditions and the bending temperatures are recorded. For sample 1, the average bending
temperature is 1004.3 degrees with a standard deviation of 8.7. For sample 2, the
average bending temperature is 1003.1 degrees with a standard deviation of 9.6.
Does this data support the claim that the average bending temperatures of the two batches
are the same?
Problem 3
A tire manufacturer claims that extensive testing shows that their tires last an average of 60,000 miles, with a standard deviation of 3,000. A random sample of 88 tires from a nationwide truck
fleet operator found the average life of the tires to be 59,324 miles. Is this result consistent
with the manufacturer's claim?