The three measures of central tendency are identical in symmetrical data sets ([[:file:statistics-overview_fig2.png|Figure 2]]) and are very different in asymmetrical data sets ([[:file:statistics-overview_fig1.png|Figure 1]]). This difference is crucial in arriving at essential estimates. For example, what is the ''most likely'' value for reserves for the next well we drill? If, as in most producing basins, there are a few huge fields and many subcommercial small fields, the most likely discovery is not the mean but the mode. Determining the shape of the frequency distribution is critical to understanding which statistic to use. (For an excellent discussion of the characteristics of petroleum data population distributions, see Harbaugh et al.<ref name=pt06r47 />) | The three measures of central tendency are identical in symmetrical data sets ([[:file:statistics-overview_fig2.png|Figure 2]]) and are very different in asymmetrical data sets ([[:file:statistics-overview_fig1.png|Figure 1]]). This difference is crucial in arriving at essential estimates. For example, what is the ''most likely'' value for reserves for the next well we drill? If, as in most producing basins, there are a few huge fields and many subcommercial small fields, the most likely discovery is not the mean but the mode. Determining the shape of the frequency distribution is critical to understanding which statistic to use. (For an excellent discussion of the characteristics of petroleum data population distributions, see Harbaugh et al.<ref name=pt06r47 />) |