At a large regional collegiate women’s swim meet, an official records the time it takes each swimmer to swim 100 meters for all swimmers who compete in only one stroke category. The following table shows the mean times and corresponding standard deviations for the collegiate women at the swim meet for each of the four stroke categories. Stroke Category Mean 100 meter Time Standard Deviation Backstroke 55.6 seconds 0.70 seconds Breaststroke 63.3 seconds 0.92 seconds Butterfly 54.4 seconds 0.94 seconds Freestyle 50.2 seconds 0.76 seconds For each of the 4 stroke categories, consider a random variable representing the time of a randomly selected swimmer in that category. What is the standard deviation of the sum of the 4 random variables?