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Simplify a complex taskGuide
Calculate an average when the groups are different sizes
Combine group means by their matching counts instead of averaging the means equally.
Illustrative resourceNot tool-testedAdults working with non-sensitive weighted average information
What you’re working towards
A source-linked weighted average with its component totals, denominator and explicit missing-data limits. This is an authored practice example; no consumer AI run has been recorded.
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Make a start
One step at a time.
2 steps
Start with the synthetic worked example or other non-sensitive inputs. Run one prompt at a time in your chosen AI tool. Replace any bracketed placeholders with the requested material, check each reply, and supply the source or earlier outputs that step needs. Paste them again if the tool lacks that context.
Start with the synthetic example, then adapt each prompt to your task.
01
Try the complete example
Open a new chat in a text AI assistant you already have permission to use. Paste all of Input from this guide, then the prompt below, in one message. Do not paste Output: that is the illustrative answer for comparison. Expect a written result that will combine group means by their matching counts instead of averaging the means equally. Different wording is fine; the source facts and rules must agree. Check it yourself: A contributes 40 points and B 60; total score 100 divided by 40 cards is 2.5. The 3.0 unweighted session mean is labeled as answering a different question, not the pooled card answer. The result lies within the group-mean range and does not describe nonrespondents or causes. If a check fails, paste: “This part is wrong: [quote it]. My source says: [quote the exact line]. Return the complete corrected result and explain the change.” Recheck before saving; if the source itself is incomplete, keep that part unresolved.
Your starting prompt
Calculate the pooled mean across the supplied cards. Show mean × count for each session, sum both scores and counts, divide and round only the final result as requested. Explain the difference from the unweighted mean of session means and state the coverage limits.
Use only the complete synthetic input pasted above. Return the finished written result. Keep missing facts unknown. Do not send, publish, order or change another service.
02
Use your own input
For your own version, open a new chat. Paste the prompt below after replacing every bracketed field. Replace related IDs, quantities, dates, rules and limits together; none of the practice facts carries over. Expect the same named deliverable using your source. Review it yourself: recompute sum(mean × count) divided by sum(count) on a calculator and check counts refer to the same measured item. If a check fails, paste: “This part is wrong: [quote it]. My source says: [quote the exact line]. Return the complete corrected result and explain the change.” Recheck before saving; if the source itself is incomplete, keep that part unresolved.
Your starting prompt
Calculate a pooled average from my group means or totals and their matching counts. Confirm units, exact versus rounded means, group coverage, missing-data policy and rounding. Show component totals, sum of valid counts and the resulting mean; distinguish it from equal-weight averaging of group means. Hold missing or incompatible inputs rather than inventing zeros.
MY INPUT
Each group mean or total: [replace with your own complete non-sensitive details, or state unknown]
Matching group counts: [replace with your own complete non-sensitive details, or state unknown]
Units: [replace with your own complete non-sensitive details, or state unknown]
Missing group policy: [replace with your own complete non-sensitive details, or state unknown]
Required rounding: [replace with your own complete non-sensitive details, or state unknown]
Use only MY INPUT for facts and constraints. Ask for an essential missing fact or conflicting rule before deciding; do not import practice-example names or numbers. Return the complete result plus unresolved questions and a source-based check list. Do not send, publish, buy, schedule or change another service.
Optional: improve the result
Keep an incomplete group visible
Show what can be computed when another group lacks its mean. This optional extension uses only the synthetic example. Return to the sample chat, or paste its full Input into a new chat first. Do not transfer the changed sample values to your own input.
Advanced prompt
For this sample only, add session C with 10 cards and an unknown mean on the same 1-to-5 item. Keep the known A/B subtotal and average. State why the exact 50-card mean is unknown, then derive its minimum and maximum possible values from C’s stated score range without inventing its actual score.
Show, then try
See the shape of the result.
This input is synthetic. The output is a written illustration of the intended result, not a verified AI-tool run.
01 / The starting point
Synthetic input
Synthetic practice input. All names, products, records and policies below are invented.
Fictional workshop feedback for the same 1-to-5-point item. A card is one observation. Session A: 10 cards, exact mean 4 points. Session B: 30 cards, exact mean 2 points. Means are exact, not rounded summaries. All supplied cards are included and no card is duplicated across groups. There are no other groups in this example.
Question: the average score across all 40 cards, not the mean of the two session averages. Show group score totals and the pooled denominator. Report the final answer to one decimal place. Do not infer satisfaction causes or responses from people who did not submit cards.
Copies text only. For image or file tasks, use the source files named in the steps too.
Illustrative answer authored for this guide; not a recorded AI response.
Group totals
A: 10 cards × 4 points per card = 40 points.
B: 30 cards × 2 points per card = 60 points.
Pooled card average
Total score = 40 + 60 = 100 points.
Total cards = 10 + 30 = 40.
100 / 40 = 2.5 points per card, to one decimal place.
Why the simple mean differs
(4 + 2) / 2 = 3.0 gives equal weight to the two sessions. It answers “What is the average of the two session means?” The requested card average gives B three times A’s weight because B has three times as many cards.
Check
The pooled result 2.5 lies between 2 and 4 and is closer to 2, the mean of the larger group. It describes only the supplied feedback cards. It does not establish the views of nonrespondents or why the sessions differ.
These checks use the worked example and its particular facts. With your own material, check your actual names, numbers, sources and rules; do not reuse the sample’s values as the answer.
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!
A few things to watch for.
Group counts must refer to the same measured item as the mean. Attendance counts are not automatically response counts.
If group means are rounded, reconstructed totals can only be approximate. Request raw totals or label the approximation.
Missing groups are not zero-score groups; a denominator without a matching numerator cannot produce a complete pooled mean.