1. The problem asks: How many hats did the knitter who sold 5 scarves sell? 2. We are given a scatter plot with points representing (Hats, Scarves) sold by different knitters. 3. Each point is in the form $(x,y)$ where $x$ is the number of hats and $y$ is the number of scarves. 4. We need to find the $x$-value (hats) corresponding to $y=5$ (scarves). 5. The data points are: $(1,5), (3,9), (4,3), (5,8), (6,1), (7,6), (9,4)$. 6. Look for the point where the $y$-coordinate is 5. 7. The point $(1,5)$ has $y=5$, so the knitter who sold 5 scarves sold $1$ hat. Final answer: The knitter who sold 5 scarves sold 1 hat.