, 3. The management of a large airline wants to estimate the average time after takeoff taken before the crew
begins serving snacks and beverages on their flights. Assuming that management has easy access to all of
the information that would be required to select flights by each proposed method, which of the following
would be reasonable methods of stratified sampling? Select all that apply.
For each day of the week, randomly select 5% of all flights that depart on that day of the week.
Divide all flights into the following 4 groups on the basis of scheduled departure time: before 9:00 am, 9:00 am
o 1:00 pm, 1:00 pm to 5:00 pm, and after 5:00 pm. Randomly select 5% of the flights in each group.
For each crew member the airline employs, randomly select 5 flights that the crew member works.
Divide the airports from which the airline's flights depart into 4 regions: Northeast, Northwest, Southwest, and
Southeast. Randomly select 5% of all flights departing from airports in each region.
4. To study the mean respiratory rate of all people in his state, Frank samples the population by dividing the
residents by towns and randomly selecting 12 of the towns. He then collects data from all the residents in
the selected towns. Which type of sampling is used?
Select the correct answer below:
Convenience sampling
Systematic sampling
Stratified sampling
Cluster sampling
5. When is stratified sampling appropriate?
begins serving snacks and beverages on their flights. Assuming that management has easy access to all of
the information that would be required to select flights by each proposed method, which of the following
would be reasonable methods of stratified sampling? Select all that apply.
For each day of the week, randomly select 5% of all flights that depart on that day of the week.
Divide all flights into the following 4 groups on the basis of scheduled departure time: before 9:00 am, 9:00 am
o 1:00 pm, 1:00 pm to 5:00 pm, and after 5:00 pm. Randomly select 5% of the flights in each group.
For each crew member the airline employs, randomly select 5 flights that the crew member works.
Divide the airports from which the airline's flights depart into 4 regions: Northeast, Northwest, Southwest, and
Southeast. Randomly select 5% of all flights departing from airports in each region.
4. To study the mean respiratory rate of all people in his state, Frank samples the population by dividing the
residents by towns and randomly selecting 12 of the towns. He then collects data from all the residents in
the selected towns. Which type of sampling is used?
Select the correct answer below:
Convenience sampling
Systematic sampling
Stratified sampling
Cluster sampling
5. When is stratified sampling appropriate?
