That arises from inaccurate sampling frame, data clarification or verification methods, reporting or coding of data, and/or specifications. It may also arise from poorly designed survey questionnaires, improper sample allocation and selection procedures, and/or errors in estimation methodology.
riff (rÉªf) n. 1. an ostinato melodic phrase accompanying a soloist in jazz or rock music. 2. any variation or improvisation, as on an idea. v.i. 3. to perform a riff. [1930â35; perhaps alter. of refrain 2] riff Past participle: riffed Gerund: riffing
gizzard. n. 1. (Zoology) the thick-walled part of a bird's stomach, in which hard food is broken up by muscular action and contact with grit and small stones. 2. (Zoology) a similar structure in many invertebrates. 3. the stomach and entrails generally.lso called ventriculus. the thick-walled, muscular lower stomach of many birds and reptiles that grinds partially digested food, often with the aid of ingested gravel. 2. a similar structure in the foregut of arthropods and annelids, often lined with chitin and small teeth.