1. The problem asks to find the value of $a$ that completes the conditional relative frequency table by row for Non-Fiction texts assigned to students. 2. The table shows relative frequencies by row, meaning each row sums to 1. For the Non-Fiction row, the sum of Poetry and Prose frequencies must equal 1: $$a + 0.9 = 1$$ 3. To find $a$, subtract 0.9 from both sides: $$a = 1 - 0.9$$ 4. Simplify the right side: $$a = 0.1$$ 5. Therefore, the value of $a$ that completes the table is $0.1$. This means 10% of Non-Fiction texts assigned are Poetry, and 90% are Prose, making the row sum to 1 as required.