For the following sample
139.9, 133.8, 81, 111, 136.4, 135.2, 53.2, 103.2, 117.2, 81.8, 28, 125, 130, 95.7, 52.6, 100, 82.1, 112.6, 80
Use default R settings to determine the 20% quantile
If the third quartile of a random variable X is then what is (decimal)