I am currently reading the book "Introduction to statistical learning" and on Page 3 there is a problem statement regarding the SMarket data (stock exchange data) fig 2.2 whose left panel states the relation shown is the percentage vs up/down trend of stock market. But here Author is saying that one box for 648 days and one for 602 days.
I don't quite get that. There is no information given for the days. Is the print faulty or am I missing something here? If someone has gone through the book and has any idea, please help me to understand the following chart.