Explanation 1
A positive z-score lies above the mean.
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Lesson 7 of 15
Express observations in standard-deviation units and investigate unusual cases without automatic deletion.
Theory
Express observations in standard-deviation units and investigate unusual cases without automatic deletion. The examples in this lesson use fictional STATLAB Academy business data and independently written explanations.
Explanation 1
A positive z-score lies above the mean.
Explanation 2
Standardization enables comparisons across units.
Explanation 3
Thresholds are investigation guides, not deletion rules.
Notation and formulas
z = (x - mean) / standard deviation
Express observations in standard-deviation units and investigate unusual cases without automatic deletion.
Interactive Mission
Z-score
2.00
2.00 standard deviations above the mean
Teaching classification: unusual
This rule starts a review. It never authorizes automatic deletion.
R connection
Run and edit the code, inspect printed output, and use the movable R Code Guide for line-by-line help.
Live R Lab
Standardize values, preserve record identifiers, and create an investigation list.
Ready to run
Worked example
Scenario
A fictional training organization needs to use standardized values and outliers to support an operational decision.
The best summary is the one that fits the question, data structure, units, and distribution.
Interpretation safeguard
Verify data entry, source, and business context before changing an unusual observation.
Dataset provenance
Original synthetic data generated for STATLAB Academy. No textbook data used.
Reflection
Name the question, data structure, units, chosen method, and one limitation.
Assistant
Coach me through Standardized Values and Outliers without giving direct quiz answers or writing my final report. Ask me to justify assumptions, units, and interpretation.
Exit check
Use a hint before checking if needed. Explanations appear only after an answer is submitted.
Checkpoint
Question 1 of 2. Answered 0/2. Passing score: 70%.