A tire manufacturer has a 60,000 mile warranty for tread life.
The manufacturer considers the overall tire quality to be
acceptable if less than 5% are worn out at 60,000 miles. The
manufacturer tests 250 tires that have been used for 60,000 miles.
They find that 3.6% of them are worn out. With this data, we test
the following hypotheses.
H0: The proportion of tires that are worn out after
60,000 miles is equal to 0.05.
Ha: The proportion of tires that are worn out after
60,000 miles is less than 0.05.
What assumption about the sample underlies the hypothesis
test?
The sample comes from a population of tires where 250 are
used for 60,000 miles.
The sample comes from a population of 250 tires that have
a 60,000 mile warranty.
The sample comes from a population of tires with 60,000
miles where 3.6% of the tires are worn out.
The sample comes from a population of tires with 60,000
miles where 5% of tires are worn out.