A statistical sample is a subset of a population observed to support statistical analysis. Samples let inferential statistics generalize from measured data to a larger population while quantifying uncertainty. section 1.1.4
In quality control, a sample can represent a batch of production measurements. Grouping observations by sample supports monitoring both process averages and variability with control charts. section 14.3
Piston-ring batches
A pandas data frame contains 200 piston-ring diameter measurements divided equally among 40 samples. Each sample identifies five measurements; descriptive statistics summarize their distribution before quality-control analysis. section 14.3
>>> print(pistons.head(10)) diameter sample 0 74.030 1 1 74.002 1 2 74.019 1 3 73.992 1 4 74.008 1 5 73.995 2 6 73.992 2 7 74.001 2 8 74.011 2 9 74.004 2
Inspect the first ten observations to see how individual diameter measurements receive sample identifiers. section 14.3
