For example, if measurements of length have been taken for bronze spearheads from one particular area and period, the measurements are represented by marking off intervals of lengths on the horizontal axis, and counting the number of spearheads falling into each division. In order to compare one set of data with another, or others, a cumulative version of the histogram may be used, where the succeeding values are added to the preceding: these are called cumulative frequency polygons, and are useful for comparative work, but are difficult to use if single histograms need to be extracted.A useful way to assess the density of rocks is to make a histogram plot of the statistical range of a set of data.There are separate graphs for the southern hemisphere and for calibration of marine data.

Sample standard errors will increase as radiometric samples size decreases (see Table 2).SYNONYMS OR RELATED TERMS: absolute dating; chronometry CATEGORY: technique DEFINITION: Any technique of dating that relies on chronological measurement such as calendars, radiocarbon dates, etc.and which give the result in calendar years before the present, or B. Most of these techniques produce results with a techniques do not.Among the most useful chronometric dating techniques are radiocarbon dating, potassium argon dating, and thermoluminescence dating.Dendrochronology, the relationship of dated ancient trees with live trees has no CATEGORY: technique DEFINITION: A graphical representation of a distribution function by means of rectangles whose widths represent intervals into which the range of observed values is divided and whose heights represent the number of observations occurring in each interval.For greater probability, the date must be taken to two standard deviations (there is a 95% certainty that the date lies between 2,800-2,000) or three standard deviations (99% certainty).A single date with a relatively large error is generally of less use than a series of dates from the same context, which may show a clustering around a central date.