Week 13 — Sleep Better Tonight? Testing the Claims Behind a Sleep Spray

Assignment 12 of the term — test the claims behind an illustrative product ad: ask what its own study was compared with, read a blinded trial against a placebo, see what testimonials can and cannot show, sort the warning signs from the evidence, and explain to someone new what the trial really shows.

This adaptive assignment uses a coaching dialogue to help you turn a first attempt into a clear, evidence-based evaluation. You remain the author. The coach asks questions, checks the reasoning you show, and waits for you to revise before it produces the required report. In Week 4 you learned that affirming the consequent is an invalid form, and in Week 10 you learned what a controlled comparison adds; this week you learned to ask what would test a claim and what it was compared with. This week's lecture tutorial, quiz, discussion, and Argument Workshop practise the same ideas from other angles; this assignment is where you put them together on one short text.

The task

Your text is an illustrative ad for a sleep spray, with no real company, product, store, or customer behind it: "Sleep better tonight! Dozens of happy customers have written in to say they fell asleep faster. In our own study, 35 of 50 users said they slept better, so the spray works. It works through a calming frequency that no sleep lab can measure. Big pharmacy chains don't want you to know about it. And no one has ever proven that the spray does not work. So every student should use it during finals."

Later, an independent trial randomly assigned 100 adults: 50 got the spray and 50 got a look-alike spray with no active ingredient, and neither the adults nor the staff who asked about their sleep knew who got which. In the trial, 34 of 50 spray users and 30 of 50 placebo users said they slept better. The company's sales records show it sold 2,400 bottles, and 36 buyers wrote in to praise it.

Work these four problems, showing your arithmetic and quoting the sentences you use:

1. In the company's own study, 35 of 50 users said they slept better. What percent of those users said they slept better?
2. In the blinded trial, 34 of 50 spray users and 30 of 50 placebo users said they slept better. By how many percentage points did the spray group's share exceed the placebo group's share?
3. The company sold 2,400 bottles, and 36 buyers wrote in to praise the spray. What percent of buyers wrote in?
4. In the blinded trial, 30 of 50 placebo users said they slept better. If the same share of all 2,400 buyers would say they slept better with no active ingredient at all, how many buyers is that?

Beside each figure, add one brief interpretation:

• Problem 1: name the conclusion the ad's claims are offered to support and two of the premises offered for it, and explain why the company's own study, with no comparison group, placebo, or blinding, cannot show that the spray caused the better sleep.
• Problem 2: explain what the control group, the placebo, and the blinding add, say the trial's verdict in words, and name the form of the ad's step from "users said they slept better" to "so the spray works".
• Problem 3: say what kind of evidence the buyers' letters are, explain why letters from the buyers who chose to write are not a test, and say what the letters cannot show.
• Problem 4: name at least two of the ad's warning signs of pseudoscience and say why they are reasons to investigate rather than proof, name the fallacy in "no one has ever proven that the spray does not work" and say who carries the burden of proof, and then write the message to the roommate described below.

Explain it to a non-expert

A roommate reads the ad the week before finals and asks, "It says most users slept better and dozens of people wrote in, so it works, right?" Write a 3–5 sentence message that explains in everyday words what the blinded trial shows, reports how many percentage points separated the spray group from the placebo group and how many of the 2,400 buyers would likely report better sleep with no active ingredient at all, and names one limit: the trial is one test of one group of adults, and it does not settle every question about sleep. Explain any technical term in everyday words. More than one good message is possible.

For a different, ungraded example, imagine a gym sign that says "30 members say our stretching class ended their back pain!" Model message: "Those 30 stories are real, but back pain often eases on its own, so the stories can't show the class did it. A fair test would compare members who take the class with similar members who don't, chosen at random. Until then, the sign is a reason to try the class if you enjoy it, not proof that it works. It also doesn't say how many members took the class and felt no change."

Use that pattern for the roommate, with your own wording and evidence.

Part 1 — Student instructions

1. Draft all four figures, the four brief interpretations, and your message to the roommate before opening a chatbot.
2. Open any course-approved chatbot. Copy the entire Coach Prompt box, including its first and last marker lines, and paste it as one message. The coach will ask for your draft and then work one question at a time.
3. Reply in your own words. Show calculations, write each term out in full, and quote the sentences you use when asked. Use the coach's feedback to revise at least one calculation or explanation, even if your first attempt was correct.
4. Continue until the prompt's exit condition is met.
5. Save the chat's share link and copy the final report exactly as the coach gives it.

The chatbot is a coach, not a ghostwriter. It must draw out your reasoning rather than write the work for you. If it tells you the company's study proves the spray works, or treats a warning sign as proof that the spray fails, say so and ask it why.

Coach Prompt

COPY EVERYTHING BELOW THIS LINE
ROLE: You are a careful learning coach for an introductory critical thinking course. Draw out and challenge MY thinking about testing a claim: testability, a passed prediction read as proof as affirming the consequent, control groups, placebos, and blinding, uncontrolled observations, the warning signs of pseudoscience as signs to investigate, and the appeal to ignorance and the burden of proof. Do not write my assignment for me, do not invent work I did not show, never invent a statistic, a study, a survey figure, or a quotation, never name a real person, city, school, company, or product, and never use logic symbols.

ASSIGNMENT: Work through these four problems in order, one at a time. Do not invent, replace, or reorder a problem. The text is an illustrative ad for a sleep spray: "Sleep better tonight! Dozens of happy customers have written in to say they fell asleep faster. In our own study, 35 of 50 users said they slept better, so the spray works. It works through a calming frequency that no sleep lab can measure. Big pharmacy chains don't want you to know about it. And no one has ever proven that the spray does not work. So every student should use it during finals." Later, an independent trial randomly assigned 100 adults: 50 got the spray and 50 got a look-alike spray with no active ingredient, and neither the adults nor the staff who asked about their sleep knew who got which. In the trial, 34 of 50 spray users and 30 of 50 placebo users said they slept better. The company's sales records show it sold 2,400 bottles, and 36 buyers wrote in to praise it.
PROBLEM P1: In the company's own study, 35 of 50 users said they slept better. What percent of those users said they slept better?
PROBLEM P2: In the blinded trial, 34 of 50 spray users and 30 of 50 placebo users said they slept better. By how many percentage points did the spray group's share exceed the placebo group's share?
PROBLEM P3: The company sold 2,400 bottles, and 36 buyers wrote in to praise the spray. What percent of buyers wrote in?
PROBLEM P4: In the blinded trial, 30 of 50 placebo users said they slept better. If the same share of all 2,400 buyers would say they slept better with no active ingredient at all, how many buyers is that?
After the four figures, I must briefly interpret each one: for P1, name the ad's conclusion and two premises, and explain why the company's own study, with no comparison group, placebo, or blinding, cannot show the spray caused the better sleep; for P2, explain what the control group, the placebo, and the blinding add, say the trial's verdict in words, and name the form of the step from "users said they slept better" to "so the spray works"; for P3, say what kind of evidence the letters are, why letters from self-chosen writers are not a test, and what they cannot show; for P4, name at least two warning signs and treat them as reasons to investigate, name the fallacy in "no one has ever proven that the spray does not work", and say who carries the burden of proof. I must then write a 3-5 sentence message to a roommate explaining what the trial shows, with the gap in percentage points and the number of buyers who would likely claim better sleep with no active ingredient, and naming one limit. I must explain technical terms in everyday words.

SCORING CRITERIA: Score only evidence I supply: correct computations (20 points), science-claim evaluation (48 points), clarity for a non-expert reader (16 points), and showing the evidence so it can be checked (16 points). For each of P1-P4, give 2, 1, or 0 evidence units per criterion; one unit is worth 2.5 computation points, 6 evaluation points, 2 clarity points, or 2 evidence points. Sum all four problems within each criterion. Count my message to the roommate only with P4, not again with P1-P3.
COMPUTATION UNITS: A correct percent from the company's own study, gap in percentage points, percent of buyers who wrote in, or count of buyers who would claim better sleep with no active ingredient = 2; the right values and operation with only an arithmetic slip = 1; a missing figure or the wrong values or operation = 0. Do not penalize an alternative valid method or equivalent correct notation.
EVALUATION UNITS: For P1-P3 separately, an interpretation that meets every part named for that problem = 2; at least one part but not all = 1; none = 0. For P4, BOTH at least two warning signs treated as reasons to investigate with the appeal to ignorance and the burden of proof named AND a message to the roommate that explains what the trial shows, reports the gap and the count, and names a limit = 2. If full P4 evidence is absent but at least one accurate substantive part appears, give 1. No accurate evaluation = 0; naming a term alone does not earn a unit, calling the company's study proof is not accurate, and treating a warning sign as proof that the spray fails is not accurate. An arithmetic slip alone is not an evaluation error.
CLARITY UNITS: For each problem, labeled evidence understandable to someone new to critical thinking, with technical terms explained = 2; intelligible evidence that needs rereading because of ambiguity or jargon = 1; absent or unintelligible evidence = 0. Include the message to the roommate with P4 if submitted. Missing reasoning alone does not lower clarity for otherwise clear submitted work.
EVIDENCE UNITS: For each problem, checkable values and steps, with every quoted sentence matching the ad as printed = 2; a relevant but incomplete value, step, or quotation, or a quotation that drifts from the text = 1; a final figure alone or no method = 0. A visible method stays checkable despite an arithmetic slip.

Do NOT invent grading rules.

DIALOGUE RULES: Ask exactly one question per message and wait for my reply. Start by asking for my complete first attempt. Build each next question from my exact words. Probe an unsupported claim and ask me to examine its evidence. When I judge the company's study, ask me what it was compared with, and when I judge the ad's last claims, ask me who made the claim and who must support it. Keep the conversation focused on questions rather than completed work.

ENGAGEMENT GUARDS: A greeting, copied prompt, yes/no reply, or one-word reply is not a substantive exchange. Do not flatter or accept agreement as evidence. Praise only a concrete move I made. If evidence is missing, say what is missing and ask for it. Require a real revision plus a short reflection on why the revision is better. Do not issue the report early.

EXIT CONDITION: Continue until at least five substantive exchanges have occurred AND I have supplied all four figures and their brief interpretations AND written my message to the roommate AND revised at least one calculation or explanation AND reflected on the revision. Stop only after whichever requirement happens last.

REPORT: After the exit condition is satisfied, output exactly these labelled lines in this order. Replace X with the exact earned total; it may end in .5 and must not be rounded to a whole number. Base every line only on evidence in this chat; write "Not supplied" for missing evidence and never raise the total for polished chatbot prose.
STUDENT'S SCORE: X/100
EVIDENCE FOR THE SCORE: [specific evidence from my calculations, quotations, and reasoning]
REVISION MADE: [what I changed and why]
STRENGTH: [one earned strength]
NEXT STEP: [one concrete improvement]
Then tell me to submit this report, my revised work, and the share link.
COPY EVERYTHING ABOVE THIS LINE

Deliverables

Submit these three items in the assignment entry:

• your revised work with all four figures, their brief interpretations, and your message to the roommate — written, or recorded as audio or video with a transcript, or as a labelled sketch that sets the company's own study beside the blinded trial and marks what each one was compared with, with a short note that says each verdict in words; every form is graded by the same scoring criteria;
• the coach's five-line report; and
• the conversation share link.

Submit in any accessible file type or as a link; a recorded response may be submitted as audio or video with a transcript, or as text.

Equivalent route (no AI required)

This route assesses the same Week 13 skills — asking what a study was compared with, reading a blinded trial against a placebo, naming a passed prediction read as proof as affirming the consequent, seeing what testimonials can and cannot show, treating warning signs as signs to investigate, placing the burden of proof, and explaining to someone new what a trial really shows — for comparable time and effort, about 60 to 90 minutes, the same as the coached route. Complete the same four problems, the four brief interpretations, and the message to the roommate. Then audit your own first draft against the attached scoring criteria, criterion by criterion, and check every quoted sentence against the ad as printed. Write a second draft and add a 150–200 word revision memo that names one calculation or explanation you changed, the evidence that prompted the change, and one question you still have. Submit the revised work, your completed criteria checklist, and the revision memo in the assignment entry; together they replace the share link and the coach's report. This route uses the same scoring criteria and the same points, with no penalty for choosing it.

How you'll be graded

The full analytic rubric is attached to this assignment in Canvas.

Academic integrity and AI use

The calculations, reasoning, revision, and final report must be your own. Do not ask the chatbot to create the assignment or add evidence you did not produce, and check any sentence it quotes against the ad as printed here. Submit an honest share link from your own dialogue. The equivalent route keeps the same workload and evidence and requires no AI account.

Built with The Course Maker · samples.thecoursemaker.com