Module 02 / Lesson 2.9 · Self-study module

Read data before declaring success

Interpret a small illustrative dataset without overclaiming.

2.0 minutes · English captions · Transcript + illustrated learning notes

This lesson has required companion reading below, including material not spoken in the video. Complete it before the assessment.

English captions available in the video player.

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Narration and visual explanations

This transcript represents the recorded lesson using conventional written abbreviations and numerals. Open View technical information to see each diagram and its explanation. This lesson has required companion reading below, including material not spoken in the video. Complete it before the assessment.

Part 1 of 4

A deliberately small dataset

View technical information · Diagram 1
A deliberately small dataset — diagram 1. Description below.
Ten ordered observations form a small illustrative dataset without process context. Key points: 10 observations; One variable; Limited context. Use the image link to enlarge.

Lesson explanation

The learning dashboard contains ten fictional temperature-indication errors in degrees Celsius: 0.1, 0.2, 0.1, 0.3, 0.2, 0.4, 0.3, 0.5, 0.4 and 0.6. They illustrate a time-ordered pattern. They are not calibration data from a real instrument and do not define a pharmaceutical tolerance.

Part 2 of 4

Calculate transparently

View technical information · Diagram 2
Calculate transparently — diagram 2. Description below.
The example calculates mean +0.31 °C, range 0.50 °C and maximum +0.60 °C. Key points: Mean 0.31 °C; Range 0.50 °C; Maximum 0.60 °C. Use the image link to enlarge.

Lesson explanation

The total is 3.1 °C across ten errors, giving a mean error of 0.31 °C. The range is 0.6 minus 0.1, or 0.5 °C. The highest error is 0.6 °C. The chart includes the underlying values in a table so that learners can check the arithmetic without relying on colour or vision. These summaries describe this small dataset only.

Part 3 of 4

Pass limits are not trend limits

View technical information · Diagram 3
Pass limits are not trend limits — diagram 3. Description below.
A numerical specification comparison differs from a trend signal or investigation trigger. Key points: Specification; Trend signal; Investigation. Use the image link to enlarge.

Lesson explanation

For arithmetic practice only, set an illustrative absolute-error limit of 0.5 °C. Nine of the ten observations meet that example limit and one does not. The limit is not an official criterion and does not qualify an instrument. The upward pattern also deserves attention even before a limit is exceeded. In a real investigation, examine measurement uncertainty, reference suitability, conditions and data integrity before drawing conclusions.

Part 4 of 4

Do not infer capability

View technical information · Diagram 4
Do not infer capability — diagram 4. Description below.
Ten points without representative conditions or a validated model cannot establish capability. Key points: Small sample; No validated model; No capability claim. Use the image link to enlarge.

Lesson explanation

Do not calculate a confident capability claim from these ten convenient values. A meaningful analysis requires a suitable study design and understanding of the measurement system and process behaviour. In the activity, change the illustrative limit, observe the count and explain what information is still missing. More green points do not create more knowledge. The purpose is to practice transparent calculation and proportionate interpretation, not to approve a system.

Required reading: signed and absolute error

Each listed value is signed error: indication minus reference, in °C. All ten happen to be positive. The decision compares |error| with the illustrative limit; equality passes this numerical comparison. A −0.6 °C error would also exceed a 0.5 °C absolute limit.

The signed mean is +0.31 °C; range is 0.50 °C. Four absolute errors exceed 0.30 °C; one exceeds 0.50 °C. Measurement uncertainty and an approved decision rule are still needed for real conformity decisions. Ten observations do not establish capability or stability.

Explore the fictional data

Signed temperature indication error (indication minus reference, °C), observations in time order. The count uses absolute magnitude; all supplied values are positive. No site data or official tolerance is represented.

Exact values underlying the chart
ObservationError (°C)
10.1
20.2
30.1
40.3
50.2
60.4
70.3
80.5
90.4
100.6

Mean 0.31 °C · Range 0.50 °C · 1 of 10 above 0.50 °C.

Changing this example limit changes only the count. It does not establish calibration, stability, capability or qualification.

Apply it · Activity 9

Calculate the mean and range, count results above 0.5 °C, and list four missing inputs before a real decision.

Open the workbook activity →

Compare with model reasoning

Mean 0.31 °C; range 0.50 °C; one value exceeds 0.5 °C. Missing inputs include justified acceptance criteria, reference/measurement uncertainty, operating conditions and representative study design.

Knowledge check

1. What can these ten fictional values establish?

Technical sources