Key idea. If at least half of the batch has no offer, then the {existing} median salary is \(0\). Removing the “no‐offer’’ students makes the new average strictly positive, hence it will certainly exceed the (old) median \(=0\). Therefore, we only need to count the years in which the number of “no‐offer’’ students is at least half of the batch size.
Median position. From the dataset for this DI set, the batch size each year is \(15\). Hence the median is the \(8^{\text{th}}\) value in the sorted list. If the number of “no‐offer’’ students in a year is \(\ge 8\), the median is \(0\), and so the new average (computed after excluding them) is definitely greater than the existing median.
Apply to the table.
Numbers without offers:
2008: \(9\), 2009: \(5\), 2010: \(20\), 2011: \(2\), 2012: \(2\), 2013: \(4\), 2014: \(15\), 2015: \(2\).
Years with at least \(8\) students without offers \(\Rightarrow\) 2008, 2010, 2014 \(\Rightarrow\) \(\boxed{3\ \text{years}}\).