STA 210 Final
In the context of hypothesis testing, good sensitivity speaks to: - ANS-the ability of the test to
reject a false HO.
In the context of screening tests, specificity is the same as: - ANS-1-the false positive rate.
in our class what do we mean when we say the results of a certain test are "not statistically
significant?" - ANS-we mean we have not been able to reject the HO with a Type I error rate that
is tolerable (usually 0.05)
A (real) test was constructed as a way of checking to see if Retinal Vein Pulsation (RVP) was
reliable as a test for Intracranial Pressure (IP). The absence of RVP is considered to be
indicative of dangerous IP. So the test looks for absence of RVP and in that sense "absence" is
a "positive" outcome. A study enrolled 189 patients and each patient was given this RVP test.
Results of the testing, along with a categorization of High or Normal IP is in the table. What is
the specificity of this test? - ANS-88%
A (real) test was constructed as a way of checking to see if Retinal Vein Pulsation (RVP) was
reliable as a test for Intracranial Pressure (IP). The absence of RVP is considered to be
indicative of dangerous IP. So the test looks for absence of RVP and in that sense "absence" is
a "positive" outcome. A study enrolled 189 patients and each patient was given this RVP test.
Results of the testing, along with a categorization of High or Normal IP is in the table. What is
the positive predictive value of this test? - ANS-70%
We worked a fair amount with data from the NHTSA's 1998 San Diego field sobriety test
validation study, issued by the agency as the report "Validation of the Standardized Field
Sobriety Test Battery at BACs Below 0.10 Percent," by Drs. Jack Stuster and Marcelline Burns.
A copy of part of this data set is attachedPreview the document. Assume a BAC of 0.04 or
above means you are (in reality) drunk. Twenty-nine participants were legally sober according to
the BACs, while 267 had BACs greater than or equal to 0.04 and were, hence, legally drunk. If
you were to take as your test that a Total FST (that is, the sum of the scores on HGN, OLS,
WAT) of 5 or more means you are drunk then what would be the false positive rate? - ANS-0.48
We worked a fair amount with data from the NHTSA's 1998 San Diego field sobriety test
validation study, issued by the agency as the report "Validation of the Standardized Field
Sobriety Test Battery at BACs Below 0.10 Percent," by Drs. Jack Stuster and Marcelline Burns.
A copy of part of this data set is attachedPreview the document. Assume a BAC of 0.04 or
above means you are (in reality) drunk. Twenty-nine participants were legally sober according to
the BACs, while 267 had BACs greater than or equal to 0.04 and were, hence, legally drunk. If
you were to take as your test that a Total FST (that is, the sum of the scores on HGN, OLS,
WAT) of 5 or more means you are drunk then what would the sensitivity be? - ANS-0.91
, We worked a fair amount with data from the NHTSA's 1998 San Diego field sobriety test
validation study, issued by the agency as the report "Validation of the Standardized Field
Sobriety Test Battery at BACs Below 0.10 Percent," by Drs. Jack Stuster and Marcelline Burns.
Assume a BAC of 0.04 or above means you are (in reality) drunk. Twenty-nine participants were
legally sober according to the BACs, while 267 had BACs greater than or equal to 0.04 and
were, hence, legally drunk. Suppose you changed your rule to require that the Total FST score
needed to say you were drunk was 2 or above instead of 5 or above. What will happen to your
false negative rate? - ANS-it decreases
We used the concepts of sensitivity and specificity to create a transition from concepts that were
familiar, to formal hypothesis testing, which was less familiar. In this transition we chose to view
a hypothesis as a screening test. In that context of testing H0 versus HA, what does it mean to
have a "false positive"? - ANS-it means you would conclude HA is true when really HO is.
You plan to take a sample of 200 voters in Kentucky and ask "Do you think former Cambridge
Analytica employee Chris Wylie should be considered a hero?" You take your sample and have
a sample proportion of 75% who say they think Snowden should be considered a hero. If you
are choosing between
HO: p < 0.73 (line under it)
HA: p > 0.73
what decision do you make and why? Take α = 0.05. Use the Standard Score Table that is
attachedPreview the document. - ANS-hair to reject HO with a p-value bigger than 0.05
If we are testing the hypothesis H0: p ≤ 0.35 versus HA: p > 0.35 and we compute z to be 0.5,
then what can you say? A copy of the Standard Score Table is attachedPreview the document. -
ANS-we fail to have convincing evidence that p is > 0.35
Reporting the results of a medical experiment, researchers claim that the difference between
two headache treatments is "statistically significant." What seems to be the alternative
hypothesis here? - ANS-the two headache treatments do not preform equally well.
An experiment is done to compare two methods of instruction, Method A and Method B. At the
end of the experiment a statistician reports a p-value of 0.001. This means: - ANS-the methods
are probably different
If someone reports that a hypothesis has been tested with an assumed Type I error rate of 0.05
and the results failed to be statistically significant, then we can say that - ANS-the p-value for
this application is > 0.05
A sample of n = 20 U.K. students is taken and each one is asked "Does knowing that many of
the basketball players U.K. recruits will go pro after one year affect your sense of attachment to
the team?" Suppose 55% in your sample said "yes, it does affect my attachment." You want to
know if it is safe for the Kernel to report that a majority of all U.K. students are likely to feel that
In the context of hypothesis testing, good sensitivity speaks to: - ANS-the ability of the test to
reject a false HO.
In the context of screening tests, specificity is the same as: - ANS-1-the false positive rate.
in our class what do we mean when we say the results of a certain test are "not statistically
significant?" - ANS-we mean we have not been able to reject the HO with a Type I error rate that
is tolerable (usually 0.05)
A (real) test was constructed as a way of checking to see if Retinal Vein Pulsation (RVP) was
reliable as a test for Intracranial Pressure (IP). The absence of RVP is considered to be
indicative of dangerous IP. So the test looks for absence of RVP and in that sense "absence" is
a "positive" outcome. A study enrolled 189 patients and each patient was given this RVP test.
Results of the testing, along with a categorization of High or Normal IP is in the table. What is
the specificity of this test? - ANS-88%
A (real) test was constructed as a way of checking to see if Retinal Vein Pulsation (RVP) was
reliable as a test for Intracranial Pressure (IP). The absence of RVP is considered to be
indicative of dangerous IP. So the test looks for absence of RVP and in that sense "absence" is
a "positive" outcome. A study enrolled 189 patients and each patient was given this RVP test.
Results of the testing, along with a categorization of High or Normal IP is in the table. What is
the positive predictive value of this test? - ANS-70%
We worked a fair amount with data from the NHTSA's 1998 San Diego field sobriety test
validation study, issued by the agency as the report "Validation of the Standardized Field
Sobriety Test Battery at BACs Below 0.10 Percent," by Drs. Jack Stuster and Marcelline Burns.
A copy of part of this data set is attachedPreview the document. Assume a BAC of 0.04 or
above means you are (in reality) drunk. Twenty-nine participants were legally sober according to
the BACs, while 267 had BACs greater than or equal to 0.04 and were, hence, legally drunk. If
you were to take as your test that a Total FST (that is, the sum of the scores on HGN, OLS,
WAT) of 5 or more means you are drunk then what would be the false positive rate? - ANS-0.48
We worked a fair amount with data from the NHTSA's 1998 San Diego field sobriety test
validation study, issued by the agency as the report "Validation of the Standardized Field
Sobriety Test Battery at BACs Below 0.10 Percent," by Drs. Jack Stuster and Marcelline Burns.
A copy of part of this data set is attachedPreview the document. Assume a BAC of 0.04 or
above means you are (in reality) drunk. Twenty-nine participants were legally sober according to
the BACs, while 267 had BACs greater than or equal to 0.04 and were, hence, legally drunk. If
you were to take as your test that a Total FST (that is, the sum of the scores on HGN, OLS,
WAT) of 5 or more means you are drunk then what would the sensitivity be? - ANS-0.91
, We worked a fair amount with data from the NHTSA's 1998 San Diego field sobriety test
validation study, issued by the agency as the report "Validation of the Standardized Field
Sobriety Test Battery at BACs Below 0.10 Percent," by Drs. Jack Stuster and Marcelline Burns.
Assume a BAC of 0.04 or above means you are (in reality) drunk. Twenty-nine participants were
legally sober according to the BACs, while 267 had BACs greater than or equal to 0.04 and
were, hence, legally drunk. Suppose you changed your rule to require that the Total FST score
needed to say you were drunk was 2 or above instead of 5 or above. What will happen to your
false negative rate? - ANS-it decreases
We used the concepts of sensitivity and specificity to create a transition from concepts that were
familiar, to formal hypothesis testing, which was less familiar. In this transition we chose to view
a hypothesis as a screening test. In that context of testing H0 versus HA, what does it mean to
have a "false positive"? - ANS-it means you would conclude HA is true when really HO is.
You plan to take a sample of 200 voters in Kentucky and ask "Do you think former Cambridge
Analytica employee Chris Wylie should be considered a hero?" You take your sample and have
a sample proportion of 75% who say they think Snowden should be considered a hero. If you
are choosing between
HO: p < 0.73 (line under it)
HA: p > 0.73
what decision do you make and why? Take α = 0.05. Use the Standard Score Table that is
attachedPreview the document. - ANS-hair to reject HO with a p-value bigger than 0.05
If we are testing the hypothesis H0: p ≤ 0.35 versus HA: p > 0.35 and we compute z to be 0.5,
then what can you say? A copy of the Standard Score Table is attachedPreview the document. -
ANS-we fail to have convincing evidence that p is > 0.35
Reporting the results of a medical experiment, researchers claim that the difference between
two headache treatments is "statistically significant." What seems to be the alternative
hypothesis here? - ANS-the two headache treatments do not preform equally well.
An experiment is done to compare two methods of instruction, Method A and Method B. At the
end of the experiment a statistician reports a p-value of 0.001. This means: - ANS-the methods
are probably different
If someone reports that a hypothesis has been tested with an assumed Type I error rate of 0.05
and the results failed to be statistically significant, then we can say that - ANS-the p-value for
this application is > 0.05
A sample of n = 20 U.K. students is taken and each one is asked "Does knowing that many of
the basketball players U.K. recruits will go pro after one year affect your sense of attachment to
the team?" Suppose 55% in your sample said "yes, it does affect my attachment." You want to
know if it is safe for the Kernel to report that a majority of all U.K. students are likely to feel that
