Final Practice Exam

A campus dining survey (illustrative) draws 500 students at random from the enrollment list, and 315 of them want a later dinner hour. What percent of this random sample wants the later hour?

Select one.

• 37 percent
• 63 percent
• 31.5 percent
• 159 percent

A gym (illustrative) finds that members who signed up for its nutrition class lost more weight, but members already eager to change their habits may be the ones who signed up. Which change would best let the gym trace a difference in weight loss to the class itself?

Select one.

• Assign members to the class or not by lottery, so eagerness and other factors split evenly
• Enroll many more members in both groups, so that each group in the comparison is much larger
• Ask the members who took the class whether they believe it helped them lose the weight
• Count the sessions each class member attended and compare that with the weight they lost

An illustrative ad for a magnetic insole says its makers will not share their test data and offers only customer stories as support. That is 2 of the 5 warning signs of pseudoscience the course lists. What follows?

Select one.

• The signs prove the insole fails, since any warning sign at all is enough to rule a product out
• The signs show nothing, since a claim nobody has tested cannot be judged in any way
• The signs are a reason to look closer, not proof that the insole does not work
• The signs show the insole works, since no test has ever shown that it fails

A student who favors replacing a campus's paper parking permits with a phone app considers the opposite. Which version states the strongest objection in standard form, under the principle of charity?

Select one.

• O1: The app's backers only want to collect drivers' personal data. So, OC: The campus should keep paper permits.
• O1: Some people dislike phones. O2: Things people dislike should be banned. So, OC: The campus should ban the parking app.
• O1: The app costs money to build. So, OC: The campus should never change how its parking works.
• O1: Some drivers have no smartphone. O2: Drivers without one could not buy a permit through the app. O3: The campus should not adopt a system that shuts some drivers out of parking. So, OC: The campus should keep a paper option.

An illustrative news story says a food additive "doubles your risk" of a rare allergy and gives no other figure. What does a careful reader need before judging how much this matters?

Select one.

• The starting risk stated out of a named base, such as how many in every 10,000 people
• Confirmation that the doubling was found by dividing by the new risk rather than the old
• A second story that repeats the doubling claim for a different additive or allergy
• The length of the article and how many experts it quotes about the additive

True or false: an argument can be valid even though its conclusion is false.

True or false.

• True
• False

A commenter waves away germ theory as "only a theory." In science, what does the word theory mean?

Select one.

• A broad explanation of many observations that has held up under extensive testing
• An educated guess that scientists have not yet found the time to check
• A tentative explanation still under test that may soon be abandoned
• A statement that no possible observation could ever show to be false

Why is a sample of 250 shoppers asked inside a stadium's team store after a home win (illustrative) a biased sample for estimating how many of a city's 300,000 residents support a new stadium tax?

Select one.

• Because it reached only people at the stadium buying team goods, the residents likeliest to favor the tax
• Because 250 shoppers is far too few to say anything useful about a whole city of 300,000 residents
• Because some of the shoppers who said yes in the store were probably not telling the truth
• Because the shoppers were questioned one at a time at the register rather than all together in a single room

An illustrative student who believes energy drinks improve focus searched with 4 phrases, each about the benefits of energy drinks, and found 12 sources: 9 support the belief and 3 question it. What does the lean of 9 to 3 tell you?

Select one.

• It may reflect the slanted search phrases more than the question, so the student should search the other side too
• The evidence supports the belief, because most of the sources the student turned up back that side of the question
• The 3 sources that question the belief are wrong, because they are outnumbered three to one
• Nothing at all, because sources found online can never count as evidence of anything

A study card sorts indicator words into two lists. Which of these words belong on the course's premise-indicator list? Select all that apply.

Select every option that applies.

• so
• for
• which shows that
• given that
• since
• hence

When a Venn diagram is used to test a syllogism, a region gets an X. What does that mark say about the region?

Select one.

• Exactly one thing is in it.
• Most members of the group are in it.
• At least one thing is in it.
• Nothing is in it.

An illustrative flyer claims: "Neighborhoods with more community gardens have less crime, so planting gardens cuts crime." Which test from the course synthesis fits this claim best?

Select one.

• The confounding check, because the claim says that one thing causes another
• A Venn diagram, because the claim sorts neighborhoods into two groups
• The value-and-fact split, because the claim concerns what a city should plant
• The source check, because the claim appears on a flyer with no author named

An illustrative club newsletter says: "The campus should run a free shuttle from the evening parking lot to the science building during lab-report week. Many evening students walk that route after dark. The shuttle is the only way to make that route safe that needs no new lighting. Running it for the four nights of lab-report week costs about 960 dollars in driver wages." When it is put in standard form, which premise is supplied under the principle of charity?

Select one.

• P4 (supplied): The campus must give evening students any service they ask for, at any cost.
• P4 (supplied): The campus should provide transport evening students need when it can do so at modest cost.
• P4 (supplied): Many evening students walk that route after dark.
• P4 (supplied): Evening students should never walk anywhere after dark.

A detective settles on the suspect whose guilt would account for every clue at once. The modern name for that kind of reasoning comes from which work?

Select one.

• Wason (1960), "On the failure to eliminate hypotheses in a conceptual task"
• Harman (1965), "The Inference to the Best Explanation", The Philosophical Review
• Tversky and Kahneman (1974), "Judgment under Uncertainty: Heuristics and Biases", Science
• Popper, The Logic of Scientific Discovery

Syllogism (illustrative): "All lifeguards hold a safety certificate. Some swim coaches are lifeguards. So some swim coaches hold a safety certificate." Which term is the middle term?

Select one.

• Swim coaches
• People who hold a safety certificate
• Lifeguards

An illustrative poll found 40 percent of a town's residents backing a new library branch last spring and 50 percent this spring. Which report states the change correctly?

Select one.

• Support rose 25 percentage points, which is a 10 percent increase
• Support rose 10 percentage points, which is a 20 percent increase
• Support rose 10 percentage points, which is a 25 percent increase
• Support rose 10 percent, which is a 25 percentage-point increase

True or false: a passage can be an argument even when it contains no premise indicator and no conclusion indicator at all.

True or false.

• True
• False

Critics of the consequence-based framework raise a standard objection to it. Which statement expresses that objection?

Select one.

• Rules and duties can clash, and following a rule can at times produce a bad result
• Results are hard to foresee, and it can seem to permit harming a few for many
• It offers little concrete direction when a person faces a hard and unusual case
• It attends to the whole person and to their judgment over the course of a life

An illustrative sleep-aid ad prints 9 glowing customer reviews. In a blinded trial, 160 adults with poor sleep are randomly assigned, 80 to the sleep aid and 80 to a look-alike placebo. After two weeks, 56 of 80 in each group sleep better. What does the trial show?

Select one.

• The sleep aid works for 70 percent of adults, so the trial confirms all 9 of the reviews
• 56 percent improved in both groups, so the aid helped only about half of the adults
• The 9 reviews outweigh the trial, since each one describes a real improvement
• 70 percent improved in both groups, so the sleep aid did no better than the placebo

A shopper (illustrative) argues: "Every phone in this display case is waterproof. The red phone is in this display case. So the red phone is waterproof." In fact, several phones in the case are not waterproof, and the red phone is one of them. How should the argument be described?

Select one.

• Invalid, because its conclusion turned out to be false.
• Valid but not sound, because a false premise fed a working form that reached a false conclusion.
• Sound, because if its premises were true its conclusion would have to be true, which is all that soundness requires.
• Inductive, because it is about phones rather than about logic.

An illustrative club newsletter argues that the campus should run a free late shuttle from the evening parking lot during lab-report week. In its map, P1 and P2 say evening students walk that route after dark and the shuttle is the only safe option without new lighting; the supplied premise P3 says the campus should provide transport students need when it can do so at modest cost; and P4 says running the shuttle for four nights costs about 960 dollars in driver wages. Where does the arrow from P4 point?

Select one.

• At P3's "modest cost" condition, which the 960-dollar figure is offered to support.
• Straight at the conclusion, as a fourth independent reason for running the shuttle.
• At P1, because the figure shows how many students walk the route.
• At an objection, because the figure is offered to answer one.

An illustrative team of 4 volunteers wins a 1,000-dollar prize. Its sign-in log shows 20, 15, 10, and 5 hours. If the team splits the prize by hours worked, how many dollars does the volunteer who logged 15 hours receive?

Select one.

• 250 dollars
• 150 dollars
• 20 dollars
• 300 dollars

In an illustrative safety report, the yearly risk of a kitchen burn falls from 8 in 10,000 people to 6 in 10,000 after a new stove design. Which statement reports the change in relative and in absolute terms?

Select one.

• A 2 percent relative decrease and 25 fewer cases per 10,000 people
• A 33 percent relative decrease and 2 fewer cases per 10,000 people
• A 25 percent relative decrease and 25 fewer cases per 10,000 people
• A 25 percent relative decrease and 2 fewer cases per 10,000 people

In an illustrative bike-shop table, 25 rainy days had low helmet sales, and 6 of those days had many repair visits. What percent of those low-sales rainy days had many repair visits?

Select one.

• 6 percent
• 25 percent
• 24 percent
• 76 percent

An illustrative online shop selling a sleep tea fails two of the four credibility questions: the seller profits from the claim and shows no evidence for it. What follows from that failed source check?

Select one.

• The tea does not work, because a failed source check proves the claim is false
• The shop is lying, since a source with a conflict of interest cannot tell the truth
• The claim is proven once another independent site repeats it word for word
• The shop has given no good reason to believe the claim, which may be true or false

An illustrative transit post reads: "Ridership on the night bus climbed 30 percent this year, so the city should keep the night route running." Which claim is the conclusion?

Select one.

• Ridership on the night bus climbed 30 percent this year
• Ridership on the night bus rose 6 percentage points this year
• A rider survey found that 45 percent of riders use the night route
• The city should keep the night bus route running

An illustrative ad's bar graph shows a rival phone's battery rating of 80 and its own rating of 84, on a vertical axis that starts at 78. The ad's bar is drawn three times as tall as the rival's. How large is the real difference?

Select one.

• A 5 percent difference, since the gap of 4 is a twentieth of the rival's 80
• A 200 percent difference, since the bars stand 2 units and 6 units tall
• A 4 percent difference, since the two ratings sit 4 apart on the scale
• A 300 percent difference, since one bar is drawn three times as tall as the other

During the Roosevelt and Landon presidential race, the Literary Digest mailed straw-poll ballots to about ten million people, drawn largely from telephone directories and car-registration lists. Roughly a quarter came back, and the magazine forecast a Landon victory, but Roosevelt won by a landslide. What does the course take from this real case?

Select one.

• A sample's size cannot rescue it: millions of ballots from slanted lists, with a skewed set of replies, still pointed the wrong way
• Mail was the whole problem, so those lists polled by telephone would have called the race for the right candidate
• Only the people who chose to reply were the problem, so the mailing lists themselves played no part in the miss
• Polling cannot say anything reliable about a nation, however carefully the people asked are chosen or counted

In the passage "A feather is light. Whatever is light cannot be dark. So a feather cannot be dark" (illustrative), "light" means low in weight in the first premise and bright in the second. Read with those two meanings, what can you say about the argument's validity?

Select one.

• It is invalid, because both premises can be true while the conclusion is false.
• It is valid, because the same word appears in both of its premises.
• It is valid, because a feather really is light in weight.
• It is invalid, because its first premise about feathers is false.

As the course uses the terms, what separates a fallacy from a false premise?

Select one.

• A fallacy is a premise that is untrue, so the flaw lies in the argument's content rather than its form.
• A fallacy is any mistaken belief a person holds, whether or not it appears in an argument.
• A fallacy is a flaw in reasoning: the premises fail to support the conclusion even if true.
• A fallacy is any argument whose conclusion turns out to be false.

An illustrative op-ed reads: "The town should plant shade trees beside the bus stops on the main road. Riders wait at those stops in full sun all afternoon. Trees give the cheapest shade that needs no upkeep once they are grown." Which of these is a stated premise, one the op-ed says out loud?

Select one.

• The town should plant shade trees beside the bus stops on the main road.
• The town should give riders comfort they need when it can do so cheaply.
• Heat can make riders who wait in the sun feel faint.
• Riders wait at those stops in full sun all afternoon.

A city planner said, "The bike lane plan will fail if the city does not add protected crossings." A flyer quotes only "The bike lane plan will fail." (illustrative) Which description fits the flyer's quotation?

Select one.

• Accurate word for word but misleading in meaning, because the cut drops a condition
• Fabricated, because the planner never said any of those words at all
• Accurate and fair, because each word it quotes really does appear in the planner's statement
• A straw man by the planner, who was replying to a weaker form of another view

Two illustrative surveys each ask 350 residents of a town whether it should build a skate park. One asks people at the town's existing skate ramp on a weekend afternoon and finds 82 percent in favor; the other draws names at random from the voter list and finds 47 percent in favor. What best explains the gap?

Select one.

• The ramp survey asked its question face to face, and people always answer more warmly in person than on paper
• Chance alone, since any two surveys of equal size will often disagree with each other by about that much
• The random survey must have worded its question about the skate park differently from the ramp survey
• How each was chosen: the ramp reached people who already skate, while the random draw gave everyone a chance

Argument (illustrative): "Of 200 fans leaving a team's home game, 170 say the city should fund a new arena, so about 85 percent of the city's residents want it." Assume its premise is true. Which verdict fits the argument?

Select one.

• Valid, because its premise is true and its conclusion follows from the figures in that premise
• Weak, because fans leaving a game are a biased sample, even though the premise is true
• Cogent, because its premise is true and it draws an inductive conclusion about the whole city
• Strong, because 200 people is a large sample for a city, whoever happened to be asked

Syllogism (illustrative): "All tulips are flowers. All roses are flowers. So all tulips are roses." Which verdict does the Venn test give?

Select one.

• Invalid, because the region of tulips that are not roses is left unshaded.
• Valid, because both premises place their group inside the same flower circle.
• Invalid, because the premise "All roses are flowers" turns out to be false.
• Valid, because every region outside the flower circle ends up shaded.

An illustrative table shows that on days when a city park sells more sunscreen, its first-aid tent sees more heat-illness visits, yet within hot days and within cool days that gap disappears. A student says the table must have miscounted, since its overall figures seem to blame sunscreen. Which reply is accurate?

Select one.

• The student is right, because a confounding factor is a kind of mistake in how the data were written down
• The student is right, because the overall shares and the within-temperature shares cannot both be correct
• The counts can all be right, and the overall figures show that sunscreen does cause heat illness after all
• The counts can all be right; the mistake is reading a cause from groups of days that differ in temperature

A campus club's flyer (illustrative) says: "A true volunteer is someone who gives up every weekend to our cause." The wording makes anyone who questions the club look like a fake volunteer. Which kind of definition is this?

Select one.

• A persuasive definition
• A reporting definition
• A precising definition
• A stipulative definition

An illustrative energy company's chart shows home heating bills for the three warmest months only, leaving out the rest of the year, to argue that its prices are low. Which misleading-graph trick is this?

Select one.

• An axis that starts higher than zero, so the heights of the bars stop matching the values
• A stretched scale that spreads a small change across most of the graph's height
• A base rate left out when a screening test is given to a large group of people
• A selected time window that shows only the stretch that suits the claim

An AI assistant's reply lists a book with an author, a publisher, and a page number, all neatly formatted (illustrative). The publisher's catalog and two library catalogs show no such book. What should you conclude?

Select one.

• The reference is genuine, since a neatly formatted reference is reliable
• The reference is invented, however convincing its format looks
• The book is a secondary source, so it was never meant to appear in a catalog
• The book exists but is out of print, so the claim it supports is safe to repeat

A recycling bin's label (illustrative) reads: "Rinse bottles before you drop them in. Food left in a bottle spoils the whole bin. A spoiled bin goes to the landfill instead of the recycler." Before the label is put in standard form, which sentence is its conclusion?

Select one.

• "Rinse bottles before you drop them in," because it is what the label wants readers to do.
• "A spoiled bin goes to the landfill instead of the recycler," because conclusions come last.
• "Food left in a bottle spoils the whole bin," because a reader could go and check it.
• None of them, because the label has no conclusion indicator.