The outlier rule is based on the inter-quartile range (upper minus lower quartile). If you have so many RAM values at 4 and 8 that those are the lower and upper quartiles, respectively, then IQR = 4, and any value above $8 + 1.5*4 = 14$ will show as a high outlier. A small-sample version follows: x = c(2,2,4,4,4,4,4,4,8,8,8,8,8,8,8,8,16,16,16,24,24) summary(x) Min. 1st Qu. Median Mean 3rd Qu. Max. 2.000 4.000 8.000 8.952 8.000 24.000 IQR(x) [1] 4 boxplot(x, horizontal=T, col="skyblue2", pch=19) [![enter image description here][1]][1] If you take logs of your observations, a boxplot may be somewhat better suited as a graphical description. y = log2(x) summary(y) Min. 1st Qu. Median Mean 3rd Qu. Max. 1.000 2.000 3.000 2.818 3.000 4.585 IQR(y) [1] 1 boxplot(y, horizontal=T, col="skyblue2", pch=19) [![enter image description here][2]][2] [1]: https://i.sstatic.net/E7CNt.png [2]: https://i.sstatic.net/F5tph.png