Checkbox disable in angular

I have a table. I have a column which has only checkboxes as values in it. I have brought all values into a table using for loop.What I did was when I enable a checkbox, I showed a message "hey" When I enable one checkbox (the message appears) but when I enable another checkbox the message disappears.The message initially comes when even one checkbox gets enabled. What I need is that until all the checkbox gets disabled the message should be there and evenwhen one or more checkboxes are there the message should be there.I am writing my code in angular.

Here is my stackblitz link https://stackblitz.com/edit/angular-oswf2h?file=src%2Fapp%2Fapp.component.ts