SharePoint Validation

[Syndicate_Admin]

Good day all, 

Could someone help me with a validation in SharePoint List. I want that a column to change when a certain choice is made. 

For example if the column have x,y,z as choices in Column A in Row 1.  Then When x is chosen then Column B of  Row 1  be update to Yes if not the it stays as is. (Attached a screen shot of what I want. 

[Syndicate_Admin]

Hello,

check calculated columns:

Examples of common formulas in lists - Microsoft Support

Kr.

[Syndicate_Admin]

Thank you will have look