"Xcopy" is not a "cmd command", it is a program, C:\Windows\System32\xcopy.exe. "Dir" is a "cmd command". You can use where.exe to search the system path folders for an executable name.
C:\>where xcopy
C:\Windows\System32\xcopy.exe
C:\>where dir
INFO: Could not find files for the given pattern(s).
C:\>where where
C:\Windows\System32\where.exe
You can schedule xcopy because it is a program. You have to use quotes for the /tr value to be able to pass arguments to the program.
schtasks /create /sc DAILY /mo 1 /st Time.Value /tn Backup_name /tr "xcopy.exe c:\rawdata c:\reports /u"
You cannot schedule "dir" by itself because it is a "cmd command"
schtasks /create /sc DAILY /mo 1 /st Time.Value /tn Backup_name /tr "cmd.exe /c dir > C:\temp\DirOutput.txt"