Readings One row per specimen, in whatever unit you measured

Specimens Measured no.

Only the first n readings below are used.

Specimen 1 units

Specimen 2 units

Specimen 3 units

Specimen 4 units

Specimen 5 units

Specimen 6 units

Specimen 7 units

Specimen 8 units

Specimen 9 units

Specimen 10 units

Against the method What the standard and the specification ask for

Specimens the Method Requires no.

ISO 13934-1 asks for five per direction; ISO 2062 asks for twenty or fifty.

Specification Minimum units

Coefficient of Variation

— %

Scatter as a percentage of the mean - the number a testing house reads first

The Result and Its Uncertainty

Mean: — units
Standard Deviation (n-1): — units
Range: — units
Standard Error of the Mean: — units
t Used for 95%: — no.
95% Confidence Half-Width: — units
Mean Could Be As Low As: — units
Lower Bound Minus Specification: — units
Specimens Short of the Method: — no.

The standard deviation is the sample form, dividing by n-1, because these specimens are a sample of the fabric and not the whole of it. The confidence half-width uses the t value for n-1 degrees of freedom rather than 1.96: at five specimens the correct interval is 42% wider than the normal approximation, and reporting the narrow one is the commonest error on a student worksheet. Read the lower bound against the specification, not the mean - a mean that clears the minimum with a lower bound beneath it has not demonstrated compliance.

Replicate Statistics for a Lab Result — free, with the formula and a worked example, at Textile School.