Calls to a customer service center last on average 2.7 minutes with a standard deviation of 1.4 minutes. An operator in the call center is required to answer 74 calls each day. Assume the call times are independent.
What is the standard deviation of the total amount of time in minutes the operator will spend on the calls each day? Give your answer to four decimal places.
I initially attempted to do:
However, this doesn't seem to work. I'm not exactly sure how to go about solving this problem.