what is the absolute test statistic?

In The Probable Error of a Mean" by William Gosset (Biometrika, Vol. VI. No. 1) published in 1908, the following values were listed for the yields of head com in pounds per acre. These values resulted from using seeds that were kiln-dried, 2009, 1915, 2011, 2463, 2180, 1925, 2122, 1482, 1542, 1443, 1535 Assuming measurements are normally distributed, test that the population mean is different from 2020, What is the absolute test statistic