How do I set a default radio button checked with boostcake?

I want to set "Medium" as the default radio button

echo $this->Form->input('priority', array(
        'type' => 'radio',
        'before' => '<label class="col col-md-3 control-label">Priority</label>',
        'legend' => false,
        'class' => 'radio-btn',
        'options' => array(
            1 => 'High',
            2 => 'Medium', 
            3 => 'Low'
        )
));

[develmts]

You can try:

    echo $this->Form->input('priority', array(
        'type' => 'radio',
        'before' => '<label class="col col-md-3 control-label">Priority</label>',
        'legend' => false,
        'class' => 'radio-btn',
        'options' => array(
            1 => 'High',
            2 => 'Medium', 
            3 => 'Low'
        )
      'value' => 'Medium'
    ));

[tino013]

Thank you, it works :)