Radiation
1. (5pts) Our knowledge of ionizing radiation and its effects
includes which of the following? (MTF):
A)
Into the late 1980s, our
assessments of low dose effects were based on extrapolation from high
doses. That situation has now
changed, as we have adequate data to directly assess effects of low levels of
radiation.
B)
A single tooth X-ray
represents 30% of the average annual background dose in the U.S.
C)
We have a precise
(accurate) understanding of the harmful effects of low doses.
D)
In cases of large
exposures, time lags of several years occur between radiation exposure
and cancer appearance, so that people exposed may die from other causes before
they have time to develop a cancer from the radiation.
2. (4pts)
Why is it difficult to measure
the harmful effects of the levels and types of ionizing radiation that we think
is most relevant to our population?
MTF
A)
Sample size: too few people are exposed to any dose
of ionizing radiation, and we donÕt know who they are, making it difficult to
assess the harm.
B)
Animal
extrapolation: rodent and other
non-humans are not useful models of cancer at the radiation doses of
interest, so we cannot do useful experiments.
C)
Extrapolation across
related hazards: there are several
different physical types of radiation, their effects on humans vary, yet we
must combine the different types with such measures as rad and rem. Two people exposed to the same number
of rads may have received different combinations of the radiation types.
D)
The increase in cell
phone and microwave oven use has made it more difficult to assess how much
radiation our population receives.
3.
(4pts) Which of the following
comprise significant portions of the U.S. average background exposures
(ÒsignificantÓ is more than 2% of U.S. average)
|
A) cosmic rays |
D) florescent lights |
F) rocks and soil |
|
B) radon |
E)
elements inside your body (potassium) |
G)
gamma rays from processed foods |
|
C) medical X-rays |
Data: Error
4.
(4 pts) Which of the following
demonstrations were used to illustrate errors in data, and which options also
correctly identify the type of error illustrated?
A)
coin flip to illustrate
sampling error
B)
Òchoose a random odd
numberÓ to illustrate sampling error
C)
width of a dime to
illustrate RPA error
D)
choose your favorite
color to illustrate bias
(5-8). For each
of the following descriptions, indicate the types of error present (the italicized phrase identifies the error). Mark a type of error
only if it is definitely present. Do not assume any more than what is
explicitly described. One answer only for each question, but an option may
be used more than once.
|
type of error: |
A) RPA |
B) sampling |
C) Human & technical |
D) Bias |
E) No error indicated |
5. (4 pts) Robert Baker
is laying square bricks to make a small, square patio. He designs the wood frame first, so
that the bricks can be laid inside the frame and fit snugly when the last brick
is set. Measuring the length a of a brick to the nearest quarter inch as 10.5Ó
(measured twice to be sure), and knowing that he wants each side of the patio to
be 20 brick lengths, he cuts the wood for a 210Ó frame (inside dimension). However, when the bricks are laid, he
finds that the 20th brick extends 2Ó beyond the frame, even though
his calculation of 20x10.5Ó = 210Ó is correct. What type of data error can plausibly explain why 20
actual brick lengths is slightly longer than his calculated length?
(one answer only)
(A)
(B) (C)
(D) (E)
6.
(4 pts) HEB wants to know how many
cashiers to have working weekday evenings. A count of customers checking out between 5:00 and 6:00 PM
every Monday for three weeks produces 420, 370, and 405; the same cashiers were
working all three days, so the difference was in the actual number of
customers, not wait time. And none
of the Mondays were holidays or special in any way. What type of error is
indicated by the difference in number of customers across the 3 different
Mondays? (one only)
(A)
(B) (C)
(D) (E)
7.
(4 pts) A pre-election poll of 1000
patrons in the Atlanta airport finds 60% are for the Republican candidate. The same procedures used later that day
in the Atlanta bus station find only 35% favor the Republican. The poll is repeated a day later in
Chicago, finding 58% of people at the airport but only 37% at the bus station
favor the Republican. What type of error is indicated by the consistent
difference in party preference between bus station and airport patrons? (one only)
(A)
(B) (C)
(D) (E)
8. (4 pts) The State Health department wishes to
assess the incidence of rabies among all bats from bridges around Austin. Two
workers go out separately and collect bats. One worker consistently finds that 2/3 of the bats are
rabid. The other worker
consistently finds that 1 in 200 bats are rabid. When the two workers compare notes, they discover that the first
worker only collected bats found on the ground, hence those bats were likely
sick; the other worker only collected bats hanging from the bridge. What type of error is represented by
the consistent difference in incidence of rabies in bats picked up off the
ground versus bats taken from the bridge?
(one only) (A)
(B) (C)
(D) (E)
9.
(4pts) For a survey, you want an
unbiased sample of 20 students who enrolled in our class and are still on the
roster. Which of the following options does the best job of reducing any
type of bias that might affect your sample? Assume that whomever you choose will complete your
survey. (One only)
A)
Obtain a list of the 200
currently enrolled students and choose 20 names randomly. For those not attending lecture,
contact them outside of class, but be sure to include them.
B)
Obtain a list of the 200
currently enrolled students. Choose every 20th man and every 20th
woman from the alphabetical list.
If any is/are not attending lecture, contact them outside of class.
C)
Assuming that 150
students will show up for lecture, choose every 7th student who
walks in the door until you have 20.
Choosing students in this spaced-out sequence reduces bias.
D)
Before class, randomly
assign numbers 1-50 to the chairs in the room (that is, randomly choose a chair
for #1, then another for #2, and so on).
When class starts, choose the students in the first 20 occupied seats on
your list.
E)
Ask for a list of
volunteers, and if they totaled more than 20, choose a subset of 20 randomly.
10-11. Do-it-yourself protocol. You are conducting an
external review/test of a DNA lab. Your job is to send two tubes to
the lab, with labels. There are several options for the content of and label on
a tube. You must decide which contents to send and how to label the tubes so
that the features of ideal data requested in the question are present from the
lab's perspective. If a tube has a person's name on it, the lab can assume that
the tube contents belong to the name of the person on the label. If a tube is
labeled with a number, the contents are unknown to the lab but known to you.
Your options for tube contents and tube labels are:
|
option |
tube label |
Contents in the tube
are from |
Blood type
|
Gender |
Vaccination status |
|
(A) |
Sam Brown |
Sam Brown |
AB |
Male |
negative |
|
(B) |
Holly Berry |
Holly Berry |
AB |
Female |
negative |
|
(C) |
Rachael King |
Rachael King |
O |
Female |
+ |
|
(D) |
#13 |
Joel Sachs |
A |
Male |
+ |
|
(E) |
#21 |
Joel Sachs |
A |
Male |
+ |
|
(F) |
#100 |
Pam Hines |
O |
Female |
negative |
|
(G) |
Anna Jenkins |
Anna Jenkins |
B |
Female |
negative |
|
(H) |
#17 |
Ulrich Mueller |
AB |
Male |
negative |
|
(I) |
No combination of tubes can
satisfy the protocol |
|
|||
In
the following questions, choose two letters among options (A)-(H) to describe
the two tubes that will be sent to the lab. The tube labels are the only
information the lab receives about the samples. If it
is possible to satisfy the protocol, the question will require exactly two
letters and only two letters -- one for each tube. Thus, the answer for a question
might be (A) & (B), or it might be (D) & (F). If more than one pair of
options are possible correct answers, fill in only one correct pair of options.
Thus, if (A) & (B) is one acceptable answer, and (C) & (D) is another
acceptable answer, fill in either (A)&(B) or (C)&(D), but not both. If a factor (such as identity, blood type, gender,
etc.) is not specified in the protocol, then that factor will be ignored in
grading the answer.
Alternatively,
if a protocol cannot be satisfied with
two from (A)-(H), fill in (I).
10. (3 pts)
Choose two tubes to guarantee replication of blood type but individual
and vaccination status are not replicated; the replication of blood type
should be blind to the lab Ð that is, the lab should not be able to tell
from the information on the tubes that the two samples have the same blood
type.
two
tubes: (A) (B) (C) (D) (E) (F) (G) (H) (I)
11. (3 pts)
Make the tubes replicated for gender and blood type but not
replicated for individual. The
replication of blood type and gender should be blind to the lab Ð that is, the
lab should not be able to tell from the information on the tubes that
the two samples have the same blood type and gender.
two
tubes: (A) (B) (C) (D) (E) (F) (G) (H) (I)
12
(4 pts). The goal is to determine lab human and technical error
rates of DNA typing through replicated typing of the same individuals. Samples are labeled with a code before
being sent for testing. Different
tubes from the same person have the same code, but tubes with samples from
different people have different codes. For this goal, is the procedure blind to
the lab performing the typing? Why
or why not? MTF
A)
It is blind, because the
lab does not know the people from which the samples came.
B)
It is not blind,
because the lab can figure out in advance which samples are the same, hence
which samples should have the same DNA type.
C)
It is not blind
regardless of the labels, because the lab can figure out which samples are the
same after they do the DNA typing.
D)
It is ambiguous
as to whether the procedure is blind, because there are ways in which the
procedure is blind and other ways in which it is not.
(13-15). For each of the
following statements, mark the appropriate letters that describe the data
design features present. Mark a data feature only if it is explicitly present
at some level in the problem description. MTF
|
(A) explicit protocol |
(C) standards |
(E) blind |
|
(B) replicates |
(D) random |
(F) none |
13. (4pts).
You live several blocks from a large refinery. One day, a neighbor gives you
some data showing that, from a survey of many of the 2,400 people living within
1/2 mile of the plant, nine have developed endocrine dysfunctions during the
last year. On the basis of these data, your neighbor claims that the refinery
is a health hazard in the community and asks your support in petitioning to
have it closed. If we interpret these data as a study to determine the health
effects of the plant, what features of ideal data are present?
(A) (B) (C) (D) (E) (F)
14. (4 pts) A middle school student decides to determine if
Fridays on the 13th day of the month are unlucky. She solicits records from emergency-room hospital admissions
and police arrest reports for all four Friday-the-13ths during a two year
period. To establish a base-line
level of expected admissions and arrests, she also obtains records from
hospitals and police for the Fridays immediately before and after each
Friday-the-13th. To guard against
errors in her analysis of the data, she has the analysis repeated by a second
person, who also does not know which group of admissions is for Friday-the-13th
and which is not.
(A) (B) (C) (D) (E) (F)
15. (4pts) A new cold medication is developed by a pharmaceutical company. To test its effectiveness at hastening recovery from colds, the company conducts a clinical trial following the procedure of a trial conducted in the previous year: medication is given to a group of 50 individuals, half of whom declare that they have a cold. After 2 days, a physician evaluates only the individuals who had declared a cold at the outset.
(A) (B) (C) (D) (E) (F)
Drug Testing
16. (4pts) Which of the following options apply to DoT drug testing protocols and lecture demonstrations? MTF
A) The DoT rules mandate split samples. This is a form of replication that can
reduce human and technical error.
B) The standards mandated by DoT drug tests include
samples from known drug offenders.
C) There is an elaborate protocol for DoT drug testing
that specifies in some fashion: replication, blind, standards, and
randomization.
D) If followed to the letter, a written procedure
minimizes errors in the data. That
is, most error creeps in because the data are not gathered strictly according
to the protocol.
E) For a person whose actual blood alcohol level is zero,
a breathalyzer can read erroneously high values of blood alcohol
concentration if they have had alcohol in their mouth in the last 10 minutes
(even though they didnÕt swallow it).
17 (4pts)What does it mean if the random match probability (RMP) is 1/billion but the lab error rate of giving false matches is 1%? In other words, how should a jury deal with those two numbers in deciding how likely it is that the forensic sample came from the suspect. (one only)
A)
The significance calculation is not affected.
B)
The random match calculation is 1/billion x probability that no error was made
(0.99)
C)
The random match calculation is 1/billion PLUS 1%
D)
You cannot calculate the significance of a match if there is a chance of human
& technical error.
18 (4pts) Which of the following properties apply to DNA
and/or DNA typing? (MTF)
A) The RMP (random match
probability) is low for DNA typing because we can work with such tiny
quantities of DNA.
B) Typing is now done with
either of two methods, STR and mitochondrial DNA.
C) DNA typing using
mitochondria is the preferred method because it has the smallest RMPs of
available methods (closer to zero).
D) Among the improvements
in DNA typing methods over the last two decades, the chance of sample mixup has
been virtually eliminated.
19-21 (3 pts each). Fill in the blanks of the ÒconsequencesÓ
column of the table with the best single option (most specific) from the list
below the table. The question
number is given in each blank. One
answer only per question.
|
Deviation from Ideal Data |
Consequences |
|
Absence of blind
proficiency testing |
19. one answer only |
|
Processing samples from
same case together |
20. one
answer only |
|
Inadequate protocols for
analysis of results |
21. one
answer only |
Your choices for consequences are:
(A) Improper calculation
of RMP (random match probability) in some cases
(B) DNA sample
degradation occurs (loss of DNA quality)
(C) The RMP threshold
for conviction will appear to be exceeded when it is actually not exceeded
(D) Sample mix-ups in a
case can go undetected
(E) This protocol is no
longer applicable because of recent changes in DNA typing methods
(F) The protocol allows
for a biased willingness to accept results
(G) Selective
reinforcement of the prime suspect
(H) The protocol
increases the likelihood of sample mix-up
(I) The full extent of
lab error rates remains unknown
(J) This protocol allows outliers of
natural variation to escape detection
22.
(4 pts) Hair matching has been shown
to be a useless method for identifying people. One of the big problems with it was the lack of a reference
database of hairs from the human population. Which of the following options about reference databases are
correct? MTF
A)
It is not possible to
accurately calculate a random match probability (RMP) without a reference
database.
B)
The RMP is 50% by
default in the absence of a reference database.
C)
A database is only
needed if the RMP is greater than zero.
It is not needed if everyone is unique and thus is not needed for
something like fingerprints or DNA typing.
D)
A reference database serves
as a standard and is therefore needed to ensure blind analysis of the data
23-25. These 3
questions address types of problems with forensic data used in court. Use the following set of options
A) bad protocols
B) bad standards (including inadequate databases, lack of
proficiency testing)
C) lack of blind
D) inadequate replication
E) failure to randomize
23. (4pts).
(MTF) What were the main
problems stated for polygraph tests (lie detector)?
(A)
(B) (C) (D) (E)
24 (4pts). (MTF)
What were the main problems stated for fingerprint matching?
(A)
(B) (C) (D) (E)
25 (4pts). (MTF)
What were the main problems stated for the use of eyewitness identification?
(A)
(B) (C) (D) (E)
26.
(4 pts.) Exam Key Code: Fill in
(AB) on question 26 to indicate your exam code. Also, fill in the correct bubbles for your name and pad
number on the scantron form.