Inference about Variables:
Part III Review
BPS chapter 22
© 2006 W.H. Freeman and Company
Inference methods
Many people believe that playing chess can have a positive effect on
reading ability. To investigate this belief, researchers took a random
sample of 53 student chess players and enrolled them in an afterschool chess instruction program. To gauge their reading ability,
each chess player took the Degree of Reading Power Test before
and after completing the program. To see whether the average
change in DRP test score is positive, which type of inference
procedure should the researchers use?
a)
b)
c)
d)
e)
One-sample t for a mean
Two-sample t for means
Matched pairs t for a mean
One-sample z for proportion
Two-sample z for proportions
Inference methods (answer)
Many people believe that playing chess can have a positive effect on
reading ability. To investigate this belief, researchers took a random
sample of 53 student chess players and enrolled them in an afterschool chess instruction program. To gauge their reading ability,
each chess player took the Degree of Reading Power Test before
and after completing the program. To see whether the average
change in DRP test score is positive, which type of inference
procedure should the researchers use?
a)
b)
c)
d)
e)
One-sample t for a mean
Two-sample t for means
Matched pairs t for a mean
One-sample z for proportion
Two-sample z for proportions
Inference methods
Many people believe that playing chess can have a positive effect on
reading ability. To investigate this belief, researchers took a random
sample of 53 student chess players and enrolled them in an afterschool chess instruction program. To gauge their reading ability,
each chess player took the Degree of Reading Power Test before
and after completing the program. To see whether the average
change in DRP test score is positive, should the researchers use a
confidence interval or a hypothesis test?
a)
b)
Confidence interval
Hypothesis test
Inference methods (answer)
Many people believe that playing chess can have a positive effect on
reading ability. To investigate this belief, researchers took a random
sample of 53 student chess players and enrolled them in an afterschool chess instruction program. To gauge their reading ability,
each chess player took the Degree of Reading Power Test before
and after completing the program. To see whether the average
change in DRP test score is positive, should the researchers use a
confidence interval or a hypothesis test?
a)
b)
Confidence interval
Hypothesis test
Inference methods
A study at Johns Hopkins investigated whether maintaining surgery
patients’ body temperatures close to normal by heating the patients
during surgery is associated with fewer event of morbid heart attack.
Surgery patients included in the study were randomly assigned to
one of two treatment groups. In the normalthermic group, patients’
core temperatures were maintained near normal 36.5 degrees
Celsius. In the hypothermic group, patients’ core temperatures
were allowed to decrease to about 34.5 degrees Celsius. To
determine whether the proportion of morbid heart attacks is less for
the normalthermic group, which type of inference procedure should
the researchers use?
a)
b)
c)
d)
e)
One-sample t for a mean
Two-sample t for means
Matched pairs t for a mean
One-sample z for proportion
Two-sample z for proportions
Inference methods (answer)
A study at Johns Hopkins investigated whether maintaining surgery
patients’ body temperatures close to normal by heating the patients
during surgery is associated with fewer event of morbid heart attack.
Surgery patients included in the study were randomly assigned to
one of two treatment groups. In the normalthermic group, patients’
core temperatures were maintained near normal 36.5 degrees
Celsius. In the hypothermic group, patients’ core temperatures
were allowed to decrease to about 34.5 degrees Celsius. To
determine whether the proportion of morbid heart attacks is less for
the normalthermic group, which type of inference procedure should
the researchers use?
a)
b)
c)
d)
e)
One-sample t for a mean
Two-sample t for means
Matched pairs t for a mean
One-sample z for proportion
Two-sample z for proportions
Inference methods
A study at Johns Hopkins investigated whether maintaining surgery
patients’ body temperatures close to normal by heating the patients
during surgery is associated with fewer event of morbid heart attack.
Surgery patients included in the study were randomly assigned to
one of two treatment groups. In the normalthermic group, patients’
core temperatures were maintained near normal 36.5 degrees
Celsius. In the hypothermic group, patients’ core temperatures
were allowed to decrease to about 34.5 degrees Celsius. To
determine whether the proportion of morbid heart attacks is less for
the normalthermic group, should the researchers use a confidence
interval or a hypothesis test?
a)
b)
Confidence interval
Hypothesis test
Inference methods (answer)
A study at Johns Hopkins investigated whether maintaining surgery
patients’ body temperatures close to normal by heating the patients
during surgery is associated with fewer event of morbid heart attack.
Surgery patients included in the study were randomly assigned to
one of two treatment groups. In the normalthermic group, patients’
core temperatures were maintained near normal 36.5 degrees
Celsius. In the hypothermic group, patients’ core temperatures
were allowed to decrease to about 34.5 degrees Celsius. To
determine whether the proportion of morbid heart attacks is less for
the normalthermic group, should the researchers use a confidence
interval or a hypothesis test?
a)
b)
Confidence interval
Hypothesis test
Inference methods
Researchers at an oil refinery northeast of San Francisco measured
carbon monoxide levels in emissions from one of their stacks on 31
separate days. Assume that these 31 measurements can be
considered a random sample of daily carbon monoxide emissions
levels. If the researchers want to estimate the mean carbon
monoxide emission level from this stack, which type of inference
procedure should they use?
a)
b)
c)
d)
e)
One-sample t for a mean
Two-sample t for means
Matched pairs t for a mean
One-sample z for proportion
Two-sample z for proportions
Inference methods (answer)
Researchers at an oil refinery northeast of San Francisco measured
carbon monoxide levels in emissions from one of their stacks on 31
separate days. Assume that these 31 measurements can be
considered a random sample of daily carbon monoxide emissions
levels. If the researchers want to estimate the mean carbon
monoxide emission level from this stack, which type of inference
procedure should they use?
a)
b)
c)
d)
e)
One-sample t for a mean
Two-sample t for means
Matched pairs t for a mean
One-sample z for proportion
Two-sample z for proportions
Inference methods
Researchers at an oil refinery northeast of San Francisco measured
carbon monoxide levels in emissions from one of their stacks on 31
separate days. Assume that these 31 measurements can be
considered a random sample of daily carbon monoxide emissions
levels. If the researchers want to estimate the mean carbon
monoxide emission level from this stack, should the researchers
use a confidence interval or a hypothesis test?
a)
b)
Confidence interval
Hypothesis test
Inference methods (answer)
Researchers at an oil refinery northeast of San Francisco measured
carbon monoxide levels in emissions from one of their stacks on 31
separate days. Assume that these 31 measurements can be
considered a random sample of daily carbon monoxide emissions
levels. If the researchers want to estimate the mean carbon
monoxide emission level from this stack, should the researchers
use a confidence interval or a hypothesis test?
a)
b)
Confidence interval
Hypothesis test
Inference methods
An experiment was conducted to see if elderly patients had more
trouble keeping their balance when loud, unpredictable noises were
made compared to younger patients who were also exposed to the
noises. To see whether the mean amount of sway differs
significantly between the elderly and younger patients, which type of
inference procedure should the researchers use?
a)
b)
c)
d)
e)
One-sample t for a mean
Two-sample t for means
Matched pairs t for a mean
One-sample z for proportion
Two-sample z for proportions
Inference methods (answer)
An experiment was conducted to see if elderly patients had more
trouble keeping their balance when loud, unpredictable noises were
made compared to younger patients who were also exposed to the
noises. To see whether the mean amount of sway differs
significantly between the elderly and younger patients, which type of
inference procedure should the researchers use?
a)
b)
c)
d)
e)
One-sample t for a mean
Two-sample t for means
Matched pairs t for a mean
One-sample z for proportion
Two-sample z for proportions
Inference methods
An experiment was conducted to see if elderly patients had more
trouble keeping their balance when loud, unpredictable noises were
made compared to younger patients who were also exposed to the
noises. To see whether the mean amount of sway differs
significantly between the elderly and younger patients, should the
researchers use a confidence interval or a hypothesis test?
a)
b)
Confidence interval
Hypothesis test
Inference methods (answer)
An experiment was conducted to see if elderly patients had more
trouble keeping their balance when loud, unpredictable noises were
made compared to younger patients who were also exposed to the
noises. To see whether the mean amount of sway differs
significantly between the elderly and younger patients, should the
researchers use a confidence interval or a hypothesis test?
a)
b)
Confidence interval
Hypothesis test
Inference methods
If researchers want to estimate the proportion of drivers that speed
(drive faster than 65 miles per hour) on a stretch of interstate west
of Hagerstown, Maryland, which type of inference procedure should
they use?
a)
b)
c)
d)
e)
One-sample t for a mean
Two-sample t for means
Matched pairs t for a mean
One-sample z for proportion
Two-sample z for proportions
Inference methods (answer)
If researchers want to estimate the proportion of drivers that speed
(drive faster than 65 miles per hour) on a stretch of interstate west
of Hagerstown, Maryland, which type of inference procedure should
they use?
a)
b)
c)
d)
e)
One-sample t for a mean
Two-sample t for means
Matched pairs t for a mean
One-sample z for proportion
Two-sample z for proportions
Inference methods
If researchers want to estimate the proportion of drivers that speed
(drive faster than 65 miles per hour) on a stretch of interstate west
of Hagerstown, Maryland, should the researchers use a confidence
interval or a hypothesis test?
a)
b)
Confidence interval
Hypothesis test
Inference methods (answer)
If researchers want to estimate the proportion of drivers that speed
(drive faster than 65 miles per hour) on a stretch of interstate west
of Hagerstown, Maryland, should the researchers use a confidence
interval or a hypothesis test?
a)
b)
Confidence interval
Hypothesis test