Whether to show tick marks on a slider survey item.
<slider> <slidertrial>
A value of 1 indicates the button will be shown, 0 indicates it will not.
The following displays the value of showticks in a text stimulus:
<text sometext>
/ items= ("showticks = <% slider.q1.showticks %>")
</text>
The following displays the value of showticks in an instruction page:
<page somepage>
showticks = <% slider.q2.showticks %>
</page>