Confidence level in the context of "Crannóg"

A crannog (/ˈkrænəɡ/; Irish: crannóg [ˈkɾˠan̪ˠoːɡ]; Scottish Gaelic: crannag [ˈkʰɾan̪ˠak]) is typically a partially or entirely artificial island, usually constructed in lakes, bogs and estuarine waters of Ireland, Scotland, and Wales. Unlike the prehistoric pile dwellings around the Alps, which were built on shores and not inundated until later, crannogs were built in the water, thus forming artificial islands.

Humans have inhabited crannogs over five millennia, from the European Neolithic Period to as late as the 17th/early-18th centuries. In Scotland there is no convincing evidence in the archaeological record of their use in the Early or Middle Bronze Age or in the Norse period. The radiocarbon dating obtained from key sites such as Oakbank and Redcastle indicates at a 95.4 per cent confidence level that they date to the Late Bronze Age to Early Iron Age. The date ranges fall after around 800 BC and so could be considered Late Bronze Age by only the narrowest of margins.