Southern States Bank and Trust monitors its drive-thru service times electronically to ensure that its speed of service is meeting the company’s goal. A sample of drive-thru times from the downtown...

Southern States Bank and Trust monitors its drive-thru service times electronically to ensure that its speed of service is meeting the company’s goal. A sample of drive-thru times from the downtown branch was recently taken and is shown here. The frequency is the number of service times and the time interval is the service time in minutes.

Compute the standard deviation for these sample data.  (Round to the nearest 2 decimal places, if needed.)