You are considering accepting a contract to provide services to a new customer group. The contract includes a performance lause on wait time. It specifies that you must have a Cp of 1.75. You know you meet the requested average wait of 7.5 minutes. The customer specifications are for +/-0.98. You will use data collected from your current customer base to determine if you are able to meet this requirement. Using the standard deviation as a measure of the natural variation, what does the standard deviation have to be to meet the requirement? Format your answer with 4 decimal places.