Below is the complete, solved decision tree for Baby Sam v. True North Hospital. 

The entire tree is shown to help you appreciate why the Expected Value came out at $5.5 million. Scroll to the far right-hand side of the tree where each scenario ends with two pieces of information.  First is a dollar figure (TOTAL =$..) that  indicates the amount owed if all the issues in the case were resolved in the manner that they are along that particular path.  (Note that each of these TOTALs includes a $1 million credit based on the codefendant's settlement.)  Second is a probability (P=0...) that indicates the likelihood of that particular scenario occurring.  The Expected Value of this case ($5.5M) is shown in a box in the lower left part of the tree, just inside the first issue.