# PWR-125 — Anomaly detection: learner worksheet Release: Revision 7T · Full Tutorial Edition Estimated time: Estimated 26 min reading and worksheet pass Difficulty: Intermediate Equipment: Common household or practice equipment — Exact 60-row synthetic dataset. Block A: 4.1, 3.8, 5.6, 4.4, 2.7, 3.6, 4.9, 4.0, 3.3, 4.7, 4.2, 3.9, 5.1, 4.6, 3.5, 4.3, 5.5, 4.0, 3.1, 4.8, 4.5, 3.7, 2.9, 4.1, 3.4, 4.9, 4.2, 3.8, 4.6, 4.0. Block B: 4.0, 3.7, 4.5, 5.0, 4.2, 3.3, 2.7, 4.8, 3.9, 4.4, 3.5, 4.1, 4.7, 3.8, 5.1, 4.3, 3.6, 4.9, 4.0, 3.2, 4.6, 5.5, 4.1, 3.9, 4.7, 4.2, 3.4, 4.8, 3.7, 4.0. Number rows A01–A30 and B01–B30 in order.; Threshold and confirmation card: reference 3.0–5.0, noise allowance ±0.2, so flag below 2.8 or above 5.2. Repeat cards for flagged rows: A03→4.4, A05→2.6, A17→5.4, B07→4.2, B22→5.4.; Hidden injected-anomaly key and confusion sheet: true anomalies are A05, A17 and B22; A03 and B07 are noise, so Block A prevalence is 2/30 and Block B prevalence 1/30. Reveal this key only after every classification and confirmation. Space: Room-scale practice space Automated structural checklist: 10 of 10 structural checks present Evidence quality/context: G1; Focused research depth Automated method-quality band: Comprehensive Method-rating basis: Structure coverage, instruction/check specificity, alternative distinctness, source troubleshooting, comparison depth and whether purpose/check fields are authored rather than derived. Editorial review: Pending manual editorial sign off ## Before you begin - [ ] I read the tutorial authority and stop conditions. - [ ] I have the required equipment/space or a declared accessible alternative. ## Canonical source context An anomaly is a value that differs from a declared reference; it is not automatically an error, fraud, disease or danger. This lesson uses synthetic temperature-sensor rows with known injected anomalies. The learner declares a range before viewing cases, flags values, checks a second measurement, reveals ground truth and reports hits, misses and false alarms at two prevalence levels. Target outcome: The learner audits 60 synthetic rows and reports a full table of hits, misses, false alarms and correct rejections plus confirmation decisions for a predeclared anomaly rule. ### Authority and setup conditions - Write that all data and devices are fictional. - Declare normal reference, anomaly threshold and confirmatory rule before opening the rows. - Set equal review time for both prevalence blocks. - Have a helper copy the row blocks and repeat cards while keeping the injected-anomaly key hidden. If you memorised the key while preparing it, use this packet as demonstration and obtain a fresh permuted set for scored practice. ### Required or supplied materials - Exact 60-row synthetic dataset. Block A: 4.1, 3.8, 5.6, 4.4, 2.7, 3.6, 4.9, 4.0, 3.3, 4.7, 4.2, 3.9, 5.1, 4.6, 3.5, 4.3, 5.5, 4.0, 3.1, 4.8, 4.5, 3.7, 2.9, 4.1, 3.4, 4.9, 4.2, 3.8, 4.6, 4.0. Block B: 4.0, 3.7, 4.5, 5.0, 4.2, 3.3, 2.7, 4.8, 3.9, 4.4, 3.5, 4.1, 4.7, 3.8, 5.1, 4.3, 3.6, 4.9, 4.0, 3.2, 4.6, 5.5, 4.1, 3.9, 4.7, 4.2, 3.4, 4.8, 3.7, 4.0. Number rows A01–A30 and B01–B30 in order. - Threshold and confirmation card: reference 3.0–5.0, noise allowance ±0.2, so flag below 2.8 or above 5.2. Repeat cards for flagged rows: A03→4.4, A05→2.6, A17→5.4, B07→4.2, B22→5.4. - Hidden injected-anomaly key and confusion sheet: true anomalies are A05, A17 and B22; A03 and B07 are noise, so Block A prevalence is 2/30 and Block B prevalence 1/30. Reveal this key only after every classification and confirmation. ## 1. Define normal and anomaly Write the reference interval, allowed measurement noise and exact flag rule. Why: An anomaly exists only relative to a declared model. Success check: Another learner can reproduce the same flag from the rule. Accessible alternative: Complete the same research action — “Write the reference interval, allowed measurement noise and exact flag rule.” — using speech-to-text, text-to-speech, enlarged text, keyboard-only navigation, shorter work blocks or a support person. Preserve this declared check: “Another learner can reproduce the same flag from the rule.” Do not convert the research task into capability practice. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## 2. Declare prevalence and costs Read the supplied expected prevalence for block one and rank the fictional cost of miss versus false alarm. Why: Base rate and costs affect a useful review design. Success check: The record states expected targets and cost priority. Accessible alternative: Complete the same research action — “Read the supplied expected prevalence for block one and rank the fictional cost of miss versus false alarm.” — using speech-to-text, text-to-speech, enlarged text, keyboard-only navigation, shorter work blocks or a support person. Preserve this declared check: “The record states expected targets and cost priority.” Do not convert the research task into capability practice. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## 3. Inspect order and local context Before classifying, note whether each value stands alone, follows a gradual drift or occurs beside a missing reading. Keep the numerical threshold unchanged. Why: Sequence context can suggest noise or system change without turning an anomaly into a cause. Success check: Every flag records its preceding value and data-quality status as context, not as proof. Accessible alternative: Complete the same research action — “Before classifying, note whether each value stands alone, follows a gradual drift or occurs beside a missing reading. Keep the numerical threshold unchanged.” — using speech-to-text, text-to-speech, enlarged text, keyboard-only navigation, shorter work blocks or a support person. Preserve this declared check: “Every flag records its preceding value and data-quality status as context, not as proof.” Do not convert the research task into capability practice. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## 4. Classify the anomaly shape Label a confirmed flag as an isolated point, a sustained level shift, a trend or an unresolved data-quality break using the supplied synthetic sequence rules. Why: Different shapes call for different confirmation questions even when the numerical threshold is identical. Success check: The shape label follows the fixture rule and remains separate from any claim about cause or danger. Accessible alternative: Replace small or visual-only information with enlarged text, high-contrast display, spoken description or tactile/verbal cueing while preserving the same decision and success check. Use calculator or spreadsheet formulas with the rule visible. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## 5. Inspect blinded rows Apply the rule to each row once and mark flag or clear without seeing the key. Why: A blinded pass preserves detection evidence. Success check: All rows receive one committed classification. Accessible alternative: Replace small or visual-only information with enlarged text, high-contrast display, spoken description or tactile/verbal cueing while preserving the same decision and success check. Offer audio values or tactile plots while preserving identical rows and timing rules. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## 6. Confirm before interpreting For each flag, open the supplied repeat-measurement card and label confirmed, not confirmed or unresolved. Why: Independent measurement can distinguish anomaly from noise. Success check: No flag is called a cause or threat. Accessible alternative: Complete “For each flag, open the supplied repeat-measurement card and label confirmed, not confirmed or unresolved.” in shorter passes, or use keyboard input, dictation or a support person, while preserving this success check: “No flag is called a cause or threat.” Provide data as an accessible table with consistent row labels. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## 7. Reveal and score Compare with injected ground truth and count hits, misses, false alarms and correct rejections. Why: All four outcomes are needed when targets are rare. Success check: The matrix totals every row. Accessible alternative: Complete the same research action — “Compare with injected ground truth and count hits, misses, false alarms and correct rejections.” — using speech-to-text, text-to-speech, enlarged text, keyboard-only navigation, shorter work blocks or a support person. Preserve this declared check: “The matrix totals every row.” Do not convert the research task into capability practice. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## 8. Change prevalence, not the rule Run block two with rarer anomalies using the same threshold and time, then compare miss and false-alarm rates. Why: Rare targets can be missed even when the detector has extensive exposure. Success check: The report shows performance by prevalence without threshold drift. Accessible alternative: Complete the same research action — “Run block two with rarer anomalies using the same threshold and time, then compare miss and false-alarm rates.” — using speech-to-text, text-to-speech, enlarged text, keyboard-only navigation, shorter work blocks or a support person. Preserve this declared check: “The report shows performance by prevalence without threshold drift.” Do not convert the research task into capability practice. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## Reflection What changed? ________________________________________________________________________________ What remains difficult? ________________________________________________________________________________ What will I repeat, adapt, ask for help with, or stop? ________________________________________________________________________________ --- Completion of this worksheet demonstrates tutorial participation only. It does not establish capability, qualification, safety clearance, diagnosis, treatment or independent validation.