Use the following information for the next two questions.

The manager at Retail Rodeo wishes to develop the appropriate process control charts to monitor the time it takes to service customers at the customer service counter. Four samples of six observations each have been taken and the following customer service times $($in minutes$)$ were recorded in the following table.

Observation

$\backslash$table$[[$Sample # $1,2,3,4,5,6,$Sample Means,$],[1,9\mathrm{.}1,8\mathrm{.}8,9\mathrm{.}6,8\mathrm{.}9,9\mathrm{.}9,9\mathrm{.}2,9\mathrm{.}25],[2,8\mathrm{.}7,8\mathrm{.}5,9\mathrm{.}3,8\mathrm{.}9,9\mathrm{.}5,9\mathrm{.}3,9\mathrm{.}03],[3,9\mathrm{.}1,8\mathrm{.}2,9\mathrm{.}7,9\mathrm{.}0,9\mathrm{.}1,11\mathrm{.}0,9\mathrm{.}35],[4,8\mathrm{.}9,8\mathrm{.}8,9\mathrm{.}5,9\mathrm{.}4,9\mathrm{.}1,9\mathrm{.}0,9\mathrm{.}12]]$

What is the value of $x$ Double Bar?

A$.$ Less than or equal to $9\mathrm{.}0$

B$.$ Greater than $9\mathrm{.}0$ but less than or equal to $9\mathrm{.}25$

C$.$ Greater than $9\mathrm{.}25$ but less than or equal to $9\mathrm{.}5$

D$.$ Greater than $9\mathrm{.}6$