Midterm exam(statistics)
1. The quality control officer at a manufacturing plant needs
to determine what percentage of items in a batch are
defective. The following are different sampling techniques
that could be used by the officer. Classify each as simple
random sample, stratified sample, systematic sample,
cluster sample, or convenience sample. (10points)
a.)The officer lists all of the batches in a given month. The
number of defective items is counted in randomly selected
batches. Random Sample
b.) The officer takes the first 10 batches and counts the
number of defective items. Convenience Sample
c.) The numbers of defective items is counted in randomly
selected batches in each shift. Stratified Sample
d.) The officer chooses every 15th batch off the line and
counts the number of defective items in each chosen
batch. Systemic Sample
e.) The officer divides the batches made in a month into
which day they were made. Then certain days are picked
and every batch made that day is counted to determine
the number of defective items. Cluster Sample
2, To evaluate whether a new fertilizer improves plant growth
more than the old fertilizer, the fertilizer developer gives
some plants the new fertilizer and others the old fertilizer. Is
this an observation or an experiment? Why? (3points)
This is an experiment because the new fertilizer (variable)
was introduced.
3 Over the years it has been said that coffee is bad for you.
When looking at the studies that have shown that coffee is
This study source was downloaded by 100000824189183 from CourseHero.com on 03-09-2022 10:18:38 GMT -06:00
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, linked to poor health, you will see that people who tend to
drink coffee don’t sleep much, tend to smoke, don’t eat
healthy, and tend to not exercise. Can you say that the coffee
is the reason for the poor health or is there a lurking variable
that is the actual cause? Explain (3points).
No, there are lurking variable. There is nothing to account
for other factors, such as genetics, stress, family
situation… to determine the effects of coffee on health,
you would need to do a study with controlled variables.
4. State the measurement scale for each (12points)
a) Temperature in degrees Celsius Interval Scale
b) Ice cream flavors available Nominal Scale
c) Pain levels on a scale from 1 to 10, (10 being the worst
pain ever) Ordinal Scale
d) Salary of employees Ratio Scale
5. Describe the type of sampling for each case and Why.?
(6points)
a) Obtain a list of patients who had surgery at all Banner
Health facilities. Divide the patients according to type of
surgery. Draw simple random samples from each group
This is a stratified sample since the patients were
separated into different stratum and then random samples
were taken from each strata.
b) Randomly select some Banner Health facilities from each
of the seven states, and then include all the patients on the
surgery lists of the states.
This is a cluster sample since all patients are questioned in
each of the selected hospitals
c) At the beginning of the year, instruct each Banner Health
facility to record any complications from every 100th surgery.
This study source was downloaded by 100000824189183 from CourseHero.com on 03-09-2022 10:18:38 GMT -06:00
https://www.coursehero.com/file/55828079/Midterm-examstat20201docx/
1. The quality control officer at a manufacturing plant needs
to determine what percentage of items in a batch are
defective. The following are different sampling techniques
that could be used by the officer. Classify each as simple
random sample, stratified sample, systematic sample,
cluster sample, or convenience sample. (10points)
a.)The officer lists all of the batches in a given month. The
number of defective items is counted in randomly selected
batches. Random Sample
b.) The officer takes the first 10 batches and counts the
number of defective items. Convenience Sample
c.) The numbers of defective items is counted in randomly
selected batches in each shift. Stratified Sample
d.) The officer chooses every 15th batch off the line and
counts the number of defective items in each chosen
batch. Systemic Sample
e.) The officer divides the batches made in a month into
which day they were made. Then certain days are picked
and every batch made that day is counted to determine
the number of defective items. Cluster Sample
2, To evaluate whether a new fertilizer improves plant growth
more than the old fertilizer, the fertilizer developer gives
some plants the new fertilizer and others the old fertilizer. Is
this an observation or an experiment? Why? (3points)
This is an experiment because the new fertilizer (variable)
was introduced.
3 Over the years it has been said that coffee is bad for you.
When looking at the studies that have shown that coffee is
This study source was downloaded by 100000824189183 from CourseHero.com on 03-09-2022 10:18:38 GMT -06:00
https://www.coursehero.com/file/55828079/Midterm-examstat20201docx/
, linked to poor health, you will see that people who tend to
drink coffee don’t sleep much, tend to smoke, don’t eat
healthy, and tend to not exercise. Can you say that the coffee
is the reason for the poor health or is there a lurking variable
that is the actual cause? Explain (3points).
No, there are lurking variable. There is nothing to account
for other factors, such as genetics, stress, family
situation… to determine the effects of coffee on health,
you would need to do a study with controlled variables.
4. State the measurement scale for each (12points)
a) Temperature in degrees Celsius Interval Scale
b) Ice cream flavors available Nominal Scale
c) Pain levels on a scale from 1 to 10, (10 being the worst
pain ever) Ordinal Scale
d) Salary of employees Ratio Scale
5. Describe the type of sampling for each case and Why.?
(6points)
a) Obtain a list of patients who had surgery at all Banner
Health facilities. Divide the patients according to type of
surgery. Draw simple random samples from each group
This is a stratified sample since the patients were
separated into different stratum and then random samples
were taken from each strata.
b) Randomly select some Banner Health facilities from each
of the seven states, and then include all the patients on the
surgery lists of the states.
This is a cluster sample since all patients are questioned in
each of the selected hospitals
c) At the beginning of the year, instruct each Banner Health
facility to record any complications from every 100th surgery.
This study source was downloaded by 100000824189183 from CourseHero.com on 03-09-2022 10:18:38 GMT -06:00
https://www.coursehero.com/file/55828079/Midterm-examstat20201docx/
