Exam 1, Biology 301D, 24 September 2002

 

104 Points Total (22 questions, 7 pages)                                   Printed name ________________

 

When finished, turn in both the Scantron and hard copy. You may write on this hard copy, but your grade will be determined by what you put on the Scantron form.  You will get this hard copy back, if you want, but it will also be posted on the web within hours of the exam.

 

None, one, all, or any combination of individual answers may apply to a question unless stated otherwise (these questions are designated “multiple T/F”).  Unless you are told that a question has just one answer, evaluate each option independently of the others to decide if it is correct.  If any part of an option is incorrect, consider the entire option incorrect.

 

(2 pts). CPS Pad number and name. Fill in the correct bubbles for your name and pad number on the scantron form. 

 

Your pad number goes in the last 3 cells of the ID number field.

 

If you don’t know your pad number, ask Bull before you turn in the scantron form.

Put your name on this hard copy too.

 

Posting.  The different versions of the exam, keys, your score, and a question-by-question accounting of your exam points will be posted on the web, usually the same afternoon/evening of the day you took the exam.


 

1 . (6 pts)  The following statements pertain to the first-day survey and the discussion of it in the following lecture.  Which statements are true?  (multiple True/False)

 

(A)   Some distributions of responses to a question contained over 90% of the responses in the combined categories of "definitely so" plus "probably so."  Thus there was a consensus in the class that those statements were likely true.

(B)   Some distributions of responses contained responses in all 7 categories (appearing moderately flat). Thus, while many people were uncertain about the truth of the statement, some considered it definitely true and others considered it definitely false. 

(C)   The responses of your class are atypical of attitudes in the U.S. public, in particular because the U.S. public is largely unaccepting of concepts for which there is no scientific evidence (e.g., the “paranormal”).

(D)   In one example, your class and previous classes exhibited a greater willingness to accept a concept couched in terms of a conspiracy theory (cover-up) than the concept stated alone.

(E)    One of the expectations we discussed was that, if we gave the same statements at the end of the semester, after you have mastered this class material on decision-making, responses of different students to a statement will be largely in agreement with each other, even for the statements which experienced a lot of scatter on day 1.

 

Scientific Method

 

2). (4 pts) The figure below shows the (unlabeled) steps of the scientific method.  Which of the following options  are true?  You are assumed to know the identity of these steps for this question.  (multiple T/F)

 

 

 

 

(A)  The scientific method cycling ends when the process enters step/loop E.

(B)   Continuing improvement toward a goal can occur with either just step/loop E or just F present (both are not required), because cycling continues through the remaining loop, even if one of the loops is missing.

(C)   The most important step is C because it is central to the most arrows.

 


3. (5 pts) Which elements of the scientific method are present?  Therapeutic Touch (TT) is a controversial nursing practice that has been taught in the UT Nursing School and elsewhere. Like other nursing practices, TT purports to improve patient healing and overall well-being. People are trained in TT methods by taking classes that provide the basic concepts, and this training enables them to use TT on their own patients. Practitioners steadfastly refuse to subject their methods to rigorous tests that would show whether patients are actually healed faster by TT than without TT, so we don't know if TT has any validity.

(A) Goal

(B) Model

(C) Data

(D) Evaluation

(E) Revision

(F) None

 

 

4. (4 pts).  Which institutions or processes were described as lacking at least evaluation (and perhaps other elements)?

 

(A)

 religion

(B)

astrology

(C) many

government agencies

(D) the criminal

justice system

(E)

car repair

(F) cooking from a

 recipe

 

 

5. (5 pts) Choose the one best answer pertaining to the scientific method in the following description?

 

David is writing a computer program to determine all whole numbers between one and a billion (109), which when multiplied by 3, give a palindrome (a palindrome reads the same way forward as backward).  The first 10 of these numbers were given to him by someone else, but there are possibly hundreds or thousands of numbers satisfying this criterion.  He starts out by writing a simple computer program.  It fails to generate even his list of 10, so he looks closely at the program and discovers that the program approximates numbers rather than treating them as exact values. He fixes this problem.  Now his program correctly provides his list of the first ten palindromes plus others; these others are correct solutions to the problem.  But the program has another difficulty:  the program stops considering numbers at 108, so David still does not know the palindromes between 108 and 109.  After calling a friend for help, neither of them is able to solve the problem.  The program remains unfixed, and David has an incomplete list of solutions to his problem.

 

A)    all elements of the scientific method are present in this example.

B)     only revision is missing – the program is never fully fixed

C)     only data are missing – there are no observations from “nature” in this example

D)    both revision and data are missing

E)     this example does not fit the scientific method, because there is an exact answer to the problem (due to its mathematical nature); thus the types of uncertainty and inexactness that characterize a true scientific problem are absent

 

Models

 

6. (8 pts) General points about models (multiple T/F)

 

  1. it is possible for the same model to be useful for some goals but useless for others
  2. for any given goal, there are usually many different models
  3. a model cannot be both accurate and convenient

still question 6:  General points about models (multiple T/F)

  1. if a model is useful for two different goals, then if it is accurate for one of the goals it is also accurate for the other goal
  2. the convenience of a model may change over time
  3. our statement that no model exactly matches what it represents is merely a (false) generalization; some models exactly match their templates, as in Xerox copies or two printings of the same book.
  4. A precise mathematical model that is properly parameterized (all the terms have been assigned their correct values) is considered an exact model of the process it represents.

 

 

7. (4 pts) One of the themes about false models is that different models have different strengths, so that by using a variety of different models, the ways in which one model is false can be compensated by another model.  That is, two models have different limitations, so their strengths can complement each other (e.g., one model may be convenient, another accurate).  Which of the following topics explicitly used or illustrated this principle?

 

A. mechanical and human tests of condoms

C. the different abstract models of dose extrapolation

B. lamp demonstration in class

D. mathematical models of epidemics

 

8,9.  Each of the following options compares two models for a particular goal.  You are asked to evaluate whether the first model compared to the second model is more accurate (question 8), or more convenient (question 9).  An option may be used no times, once, or twice.  Use lecture and the book as the basis for your answers.  (multiple answers)

(A)        The airburst test instead of volunteers in tests of condoms

(B)         Yeast instead of mice in toxicity tests of chemicals for human exposures

(C)         Humans accidentally exposed to dioxin instead of guinea pigs deliberately exposed to dioxin in testing the toxicity of dioxin for humans

(D)        Low doses of a pesticide versus high doses of it fed to rats for testing whether traces of the pesticide in food causes cancer.

(E)         LD50 in rats versus assays of tumor formation as a model of a chemical’s ability to cause cancer in rats

8 (4 pts).  In which options is the first of the two models more accurate?  (A)  (B)  (C)  (D)  (E)

 

9 (4 pts).  In which options is the first of the two models more convenient?  (A)  (B)  (C)  (D)  (E) 

 

10 (5 pts).  Your responses to questions on this exam would be a false model of what you have learned and retained in this class if/because:  (multiple T/F)

(A)   You interpreted the question differently than it was intended

(B)   You forgot some of the material needed to answer the question

(C)   You accidentally filled in the wrong blank from what you intended

(D)   Someone copied your answers and got the same score as you

(E)    Your score differed from the class average score

(F)    The exam questions did not cover all the material you learned

 

 11. (5 pts) Are the first 10 students in the Bio301D class roster a useful model or false model of the 400 students in Bio301D? (multiple T/F)

(A) false:  grades given to the 10 may not match the grades given to the other 390 students in the class

(B) useful:  understanding why the 10 students missed certain questions on exam 1 could help the instructor understand why other students missed those questions.

(C) false:  if none of the 10 required special accommodations (students with disabilities), that does not guarantee that none of the other students require special accommodations

(D) useful:  knowing how those 10 students felt about exam 1 would help the instructor know how the other 390 felt.

HIV and Mathematical models in epidemiology

12. (5 pts)  From the Notes and lecture, indicate which of the following elements of the models template apply (in the way stated below) to our understanding of the timing of HIV transmission. (multiple T/F)

(A)  Goal: to determine how soon after the person becomes infected that they can infect someone else with the virus and how this timing impacts the spread of the HIV epidemic

(B)   Model: a relatively small amount of transmission during the "primary infection" (phase I) can account for the rapid spread of HIV in populations (the primary infection is the early peak of HIV in the blood)

(C)   Data: direct monitoring of couples (one HIV+, one HIV-) has shown that transmission to the uninfected partner is especially likely when the infected partner is entering the primary infection stage

(D)  Evaluation: the model of early transmission has not been rejected (refuted) by scientific studies

 

 

13. (4 pts) Which of the following interest rate schemes yields the most money over 10 years?

 

A)    1/12% compounded monthly

B)     1% compounded annually

C)     10% compounded every 10 years

D)    There is no difference in the money accumulated.

 

Condoms

 

14. (4 pts) Which condom tests are useful (accepted) for determining whether an intact condom will block transmission of an STD (e.g., HIV)?  (choose the best answer)

  1. the airburst test
  2. mechanical tests
  3. volunteer tests with discordant couples
  4. the water leak test

 

15. (4 pts)  It was suggested that industry prefers quality control tests such as the airburst test because of which factors (choose the best answer):

 

A. Accuracy

C. Uniformity

E. Accuracy & uniformity

G. Accuracy,

convenience &

uniformity

B. Convenience

D. Accuracy & Convenience

F. Convenience & uniformity

 

Extrapolating Health Risks

 

16. (4 pts) (multiple T/F) The abstract models (graphs) we considered in extrapolating from high to low doses

  1. all had the property of greater risks at high doses than at low doses (on the scale shown)
  2. all showed that cutting the dose in half also cut the risk in half
  3. could apply to cancer rates, death rates (toxicity), or countless other bad consequences of exposure
  4. concerned exposure to radiation, dioxin, and chloroform but not other substances

 

17. (4 pts) Of the examples discussed, which one(s) highlighted problems in extrapolation from lab animals to humans? (multiple T/F)

  1. dioxin
  2. fetal alcohol syndrome
  3. tobacco smoke
  4. rodent models of carcinogenesis
  5. the U.S. standard of acceptable limits based on animal LD50/million

 

18. (3 pts) Which graph(s) depict an accelerating risk of exposure? (none, one, or many answers)

 

 

 

19. (4 pts) (multiple T/F)  

 A MSDS (material safety data sheet) is

  1. an accepted/useful model of a chemical’s effect on you
  2. may describe the effect of a chemical on non-humans
  3. described only those consequences of exposure that have been estimated beyond a reasonable doubt
  4. lacks a great deal of potentially useful information

 

 

 

20. (4 pts) There were several messages given in the lectures and chapter on extrapolating health risks.  Identify which one of the following options is wrong, or choose option e if none is wrong.  (one answer only)

 

  1. a variety of models is used to estimate the risks from human exposure to hazardous substances
  2. there are currently many gaps in what we know about the human risks of chemicals (and other substances)
  3. as methods of risk determination have improved, we have realized that the true risks are greater than the risks estimated by older methods (for most substances)
  4. the linear dose extrapolation model is supported in some cases but not others
  5. All the above are true

 

 

21. (10 pts) Each of the following options lists or refers to a theme in the course notes and then offers an explanation of what it means. Which of these statements about Meaning are true? (multiple T/F)

(A) Theme: One-to-many, many-to-one. Meaning: when pursuing one goal, we may at first use many different models (e.g., the airburst test and water-leak test of condoms), but eventually, we will converge on using just a single model for achieving that goal.

(B) Theme: the goal determines model usefulness. Meaning: the value (usefulness) of a particular model depends on what goal we are trying to achieve.

(C) Theme: The importance of model accuracy. Meaning: ultimately, the most useful model (the one we most want to use) is the one that most closely matches what we are trying to represent. For example, human subjects are the most useful model for studying whether a food additive causes of cancer in humans, as opposed to mice or bacteria, because mice and bacteria are not humans.

(D) Theme: the scientific method is a cyclic method that, through repetitions, enables progress toward a goal. Meaning: the scientific method is fundamentally similar to  trial and error.

(E) Theme: pieces and parts as models. Meaning: a model of something is more likely to be useful the closer it comes to representing the "whole" of it, rather than just a part of it.

 

(F) Theme: ACU (accuracy, convenience, uniformity). Meaning: ultimately, the most useful model (the one we most want to use) is the one that is the most accurate.  Convenient but inaccurate models are ultimately going to be replaced by more accurate ones.

(G) Theme: All models must be falsifiable (refutable). Meaning: just another way of saying that all models are false.

 

22. (2 pts.) Exam Key Code: Fill in (AB) on question 22 to indicate your exam code.