1. **State the problem:** We have a total of 19 items in the universal set $\xi$. Sets $M$ and $N$ are subsets of $\xi$ with the following counts:
- $8$ items in $M$ only
- $2$ items in both $M$ and $N$
- $4$ items in $N$ only
- $5$ items outside both $M$ and $N$
We want to find the probability that a randomly chosen item is in $M' \cap N$, which means the item is **not in $M$ but in $N$**.
2. **Recall the formula:** The probability of an event $A$ is given by
$$\text{P}(A) = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}}$$
3. **Identify the favorable outcomes:** The set $M' \cap N$ includes items that are in $N$ but not in $M$. From the diagram, these are the items in $N$ only, which is $4$.
4. **Calculate the probability:**
$$\text{P}(M' \cap N) = \frac{4}{19}$$
5. **Final answer:** The probability that an item chosen at random is in $M' \cap N$ is
$$\boxed{\frac{4}{19}}$$
Probability Venn 717F1C
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