1
STA 210 Final Questions with Correct
Answers for Specific Exam Mail
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
Pretest - Stuvia US
,2
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
Pretest - Stuvia US
,3
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
Pretest - Stuvia US
, 4
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
Pretest - Stuvia US
STA 210 Final Questions with Correct
Answers for Specific Exam Mail
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
Pretest - Stuvia US
,2
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
Pretest - Stuvia US
,3
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
Pretest - Stuvia US
, 4
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
Pretest - Stuvia US
