Final answer:
The ability-ranking scale described is an example of an ordinal scale, which allows for ranking data in a specific order but does not provide precise information about the magnitude of differences between ranks.
Step-by-step explanation:
The scale ranking abilities from unable, somewhat able, able, very able, to extremely able is an example of an ordinal scale. This measurement scale involves a sequence where data can be placed in an ordered sequence but the differences between the data points cannot be measured precisely.
Ordinal scales are common in questionnaires or surveys where responses are categorized based on levels of agreement or effectiveness. For instance, an employee performance review might use an ordinal scale to rank performance from poor to excellent. Another example is a hierarchy list, which, like the hierarchical scale, orders entities based on relative importance.
Unlike nominal scales, which simply categorize data without an intrinsic order, and unlike ratio scales, which include a true zero point allowing for calculation of ratios, an ordinal scale provides a rank order only without giving information about the magnitude of differences between ranks.