A standard installation of SharePoint Server 2016 will only create a 14 folder and a 16 folder. There is no 15 folder in the hive (i.e. at ...\Web Server Extensions\15). The reason they did this was to not break compatibility with v15 sites.
Furthermore there's no compatibility level available in 2016 (yes the switch is there, but there's no point). All sites are v15 and there is no backwards compatibility with v14.5. This was for ease of migration.
This was essentially a feature for Microsoft and is why all sites must be in v15 compat mode prior to upgrading to 2016.
About standard installation means you were installed SharePoint 2016 directly , such as manually run the prerequest.exe, setup.exe and so on . not upgrade from 2013 .