Final answer:
Jack Joyner's method of inspecting every fifth casting to decide the production quality is an example of inferential statistics, where a sample is used to estimate a population parameter.
Step-by-step explanation:
Jack Joyner's approach of inspecting every fifth casting during the evening shift and basing his decision on less than 1% of those being defective is an example of inferential statistics. This facet of statistics involves estimating a population parameter from a sample statistic. In this case, Jack used a sample to estimate the quality of the entire shift’s production and make a decision about whether it met acceptable standards.