Because in maths if you are 5 and above you round up.
Why would you report 7.1 as 8? I think that maybe you are thinking that rounding up to 8 may be more conservative. I dont think that is correct as parameters being higher or lower can be conservative or unconservative in specific applications.
Ron I routinely see atterbergs to 2 decimals. Same with settlement, we have many clients that wont accept a bearing pressure if its 25.2mm. HAS TO BE 25mm OR BELOW!!! Some ppl just dont get it.
And also Geokhan, you need to start giving some more information with your questions. What "sand equivalent" test, BS, ASTM etc? In many standards there is a requirement of the standard to report numbers in a certain fashion.