Display and hide content using checkbox in Options Framework Theme

‘true’ should be ‘1’:

$options[] = array(
    'name' => __('Input Checkbox Name', 'options_framework_theme'),
    'desc' => __('Check to display.'),
    'id' => 'example_checkbox_2',
    'std' => '1',
    'type' => 'checkbox'
);

and:

<?php if ( 1 == of_get_option('example_checkbox2') ) { ?>
        <p>checked</p>
    <?php } else { ?>
        <p>unchecked</p>
<?php } ?>

error code: 523