  Suppose the lifetime of a large sample of batteries in routine use is
measured. A confidence interval is computed to 394 plus/minus 1.96 times 4.6
days. The standard interpretation is that if we repeatedly draw samples and
compute confidence intervals, about 95% of the intervals will cover the unknown
true lifetime. What can be said about the particular interval 394 plus/minus
1.96 times 4.6 has not been clear. We clarify this by using an epistemic
interpretation of probability. The conclusion is that a realised (computed)
confidence interval covers the parameter with the probability given by the
confidence level is a valid statement, unless there are relevant and
recognisable subsets of the sample.
