Here is the table showing the batting averages for all 1105 players who batted in at least 20 innings up to 25 Oct 2019:
The averages range from 99.94 (DG Bradman) to 2.00 (M Mbangwa).
The mean of these averages is 27.07, and those closest to it are KR Rutherford, JJ Lyons and PA Strang.
Looking at other measures of central tendency:
First quartile: 36.16 (Wasim Raja)
Median: 26.52 (PR Reiffel, RW Marsh)
Third quartile: 16.28 (RW Taylor, BL Cairns)