Some marathons allow two runners to "split" the marathon by each running a half marathon. Alice ...

Some marathons allow two runners to "split" the marathon by each running a half marathon. Alice and Sharon plan to split a marathon. Alice's half-marathon times average 92 minutes with a standard deviation of 4 minutes, and Sharon's half-marathon times average 96 minutes with a standard deviation of 2 minutes. Assume that the women's half-marathon times are independent. The expected time for Alice and Sharon to complete a full marathon is 92 + 96 = 188 minutes. What is the standard deviation of their total time?

▸ 2 minutes

▸ 20 minutes

▸ 4.5 minutes

▸ 6 minutes

▸ It cannot be determined.