How to format text in the title attribute of ?

[Paul Spencer]

I am including a Double in the title of <t:outputText>.  The problem the 
 default formating is undesired.
The tag:
 <t:outputText
    value="#{tripSummary.columnValue.idleSeconds.sum}"
    title="Mean idle time is 
#{tripSummary.columnValue.idleSeconds.mean} minutes">
  <f:convertNumber maxFractionDigits="0" />
 </t:outputText>
Displays "Mean idle time is 6.977777777777777 minutes"  as tool tip.

I prefer "Mean idle time is 7 minutes".  The question is how can I 
format the text?

Paul Spencer