Module 1
Question 1
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Question 1 - 2
Scientific tests are intended to give us facts to reason from in understanding the world. A
"positive" result tells us that the condition tested for exists. A -negative' result suggests that it
does not exist, however, in the real-world tests do not offer guarantees. Most actual tests are
indirect, measuring variables conveniently correlated with the condition of interest (for
example, we see whether litmus paper turns red to test for "acidity", meaning hydronium ions
are in the solution). Most tests have an error rate, resulting in both "false positive" and "false
negative" results. This means scientists need to be aware of probabilities, and able to
calculate what proportion of seemingly positive observations actually involve the condition
of interest.
A typical example is breast cancer screening. Assume that 1% of women who participate in
routine screening have breast cancer. The testing process is not perfect: of those with breast
cancer, only 80% will get a positive result in their mammogram. On the other hand, for those
without breast cancer, 98% will get a negative result in their mammogram.
1. If 10,000 women are screened for breast cancer, on average how many false positive
results and how many true positive results would appear?
Zero false positive, 100 true positive.
80 false positive, 198 true positive.
198 false positive, 80 true positive.
278 true positive results.
Correct Answer: C Explanation:
We are told that 1% of the women tested have breast cancer, so 99% do not. Of those with
cancer, 80% test positive (so 20% test negative). Of those who do not have cancer, 98% test
negative (so 2% test positive). That gives 80 true positive results, and 198 false positive
results.
,Question 2
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Question 1 - 2
Scientific tests are intended to give us facts to reason from in understanding the world. A
"positive" result tells us that the condition tested for exists. A -negative' result suggests that it
does not exist, However, in the real-world tests do not offer guarantees. Most actual tests are
indirect, measuring variables conveniently correlated with the condition of interest (for
example, we see whether litmus paper turns red to test for "acidity", meaning hydronium ions
are in the solution). Most tests have an error rate, resulting in both "false positive" and "false
negative" results. This means scientists need to be aware of probabilities, and able to
calculate what proportion of seemingly positive observations actually involve the condition
of interest.
A typical example is breast cancer screening. Assume that 1% of women who participate in
routine screening have breast cancer. The testing process is not perfect: of those with breast
cancer, only 80% will get a positive result in their mammogram. On the other hand, for those
without breast cancer, 98% will get a negative result in their mammogram.
2. Working as a family doctor, you routinely advise your women patients over the age of 50
to participate in screening programs for breast cancer. One of your patients is Mabel Howard,
a 57-year-old woman with three adult children, who has recently taken up skiing.
If Mabel's mammogram returned a positive result for breast cancer, what would be the
probability that she actually had breast cancer?
100%
80%
40.4%
, 28.8%
Correct Answer: D Explanation:
We had 80 true positive and 198 false positive results, giving a total of 278 positive results.
The probability of actually having cancer for someone who tests positive is then ( =
28.776%) which rounds to 28.8%. Eliminating other options may be quicker than calculating
this directly.
Question 3
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Question 3 - 4
Beneath the multifarious variety of living organisms is a deep order. When we admire
striking plumage or agile maneuvers, we pick out complex features which, though diverse,
are the very opposite of simple chaos. Like ornate sandcastles on a beach, without active
maintenance, these structures and behaviors would, in the long run, be washed away by
successive tides of genetic mutation. Besides mutation, there is remodeling, where existing
features form a scaffold to build something new. However, as in renovating one's house while
living in it, the extent of this remodeling is limited by requirements of daily life. A toilet or
kitchen once installed receives daily use, and is not readily altered.
3. Which of the following lists in order describe the three analogies employed in the above
passage?
Living organisms to sand-castles, genetic mutation to building scaffolds, a kitchen to
structural features of an organism, which support its current way of life.
Sand-castles to life-forms, genetic mutation to building scaffolds, renovating a house
to the process where one complex feature of an organism is adapted to something
different.
Genetic mutation to ocean waves, building scaffolds to existing structural features of
an organism, a toilet to structural features of an organism which support its current
way of life.
Biological structures to sand-castles, building scaffolds to functional features of an
organism, renovating a house to the process by which complex features of an
organism are actively maintained against external forces.
Correct Answer: C
Explanation:
Options (a) and (b) incorrectly include an analogy between living organisms and sand-castles.
The analogy is between structures and behaviors of organisms and sandcastles. Option (d)
incorrectly suggests that the house renovation analogy is about maintenance of complex
features, when in fact it is about complex changes in organisms over time.
Question 4
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, Question 3 - 4
Beneath the multifarious variety of living organisms is a deep order. When we admire
striking plumage or agile maneuvers, we pick out complex features which, though diverse,
are the very opposite of simple chaos. Like ornate sandcastles on a beach, without active
maintenance, these structures and behaviors would, in the long run, be washed away by
successive tides of genetic mutation. Besides mutation, there is remodeling, where existing
features form a scaffold to build something new. However, as in renovating one's house while
living in it, the extent of this remodeling is limited by requirements of daily life. A toilet or
kitchen once installed receives daily use, and is not readily altered.
4. Which of the following best captures the main point of the above passage?
The complex order we see in living creatures could not have arisen from simple
chaos — like sand-castles and houses, living creatures are designed.
Like sand-castles and houses, living organisms display complex order. But unlike
sand-castles and houses, living creatures have no designer.
Active maintenance processes allow houses and sandcastles to display complex
order in a changing environment, just as living creatures do.
Complex order that continues to exist in a changing environment requires active
maintenance processes. Living creatures are an example of this.
Correct Answer: D
Explanation:
Options (a) and (b) go beyond scope, making claims about creation or intelligent design.
There is no strong suggestion that the author takes a position on these issues. Option (c)
misconstrues the analogies – the point about sandcastles is that they do not display complex
order in a changing environment.
Question 5
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Question 5 - 6
Twins, Daphne and George, were adopted at 'birth by different families. After years of
searching for one another they made a contact and arranged a reunion, George brought along
his son Gavin and Daphne brought along her daughter Louise to the meeting.
5. How many family relationships were represented at the meeting?
4
6
