Set which radio button of a group is checked / selected by default in pdf javascript

I am constructing a dialog in pdf javascript, which contains multiple groups of radio buttons.
What i don’t get is how to set a default selection for any one group.
The example i have attached below is shortened to only one radio button group.
I do believe that using a check box for this task would probably be better it is not my decision to make.

var oDlg = {
        result: "cancel",
        DoDialog: function() { return app.execDialog(this); },
       
        complete: false,

        commit: function(dialog) {
            var result = dialog.store();

            this.complete = result["completeTrue"];
        },

        description: {
            name: "ADialog", 
            elements: 
            [ 
                {
                    type: "view",
                    elements:
                    [
                        {
                            type: "view",
                            align_children: "align_row",
                            elements:
                            [
                                {
                                    name: "Is complete?", 
                                    type: "static_text",
                                    char_width: 15,
                                },
                                {
                                    item_id: "completeTrue", 
                                    group_id: "complete", 
                                    type: "radio", char_width: 15,
                                    name: "Yes" 
                                },
                                {
                                    item_id: "completeFalse",
                                    group_id: "complete",
                                    type: "radio",
                                    char_width: 15,
                                    name: "No" },
                            ]
                        },
                    ]
                },
                { type: "ok_cancel", },
            ]
        }
    };

I tried checked and selected in various different ways, and couldn’t get that to work. Googling resulted in me trying this.getField("completed").value = someIndex; which also did nothing.
The expected result is that instead of the “Yes” radio button being selected when the dialog opens, the “No” button is selected.