Stud wall - screwed into joist or floor board only?

[Dee12345]

Hi,

I want to put up a stud wall on the 1st floor.

Do I have to screw the bottom or top stud plate into the joist below/above or can I just attach to the bottom stud into floor board and the top stud into the ceiling plaster?

The joist run at right angle to the stud.

Thanks
Dee

 

[johnny2007]

Joists

 

[dontbelieveawordofit]

or if theres no fix get up there and put a timber in .

 

[Dee12345]

noted!

thanks