Marginal Distribution
1. **State the problem:** We have a 2x3 data table with values:
$$\begin{array}{c|ccc}
& x_1 & x_2 & x_3 \\
\hline
y_1 & 20 & 25 & 30 \\
y_2 & 30 & 15 & 50
\end{array}$$
We need to construct the frequency marginal distribution for this data.
2. **Understand marginal distribution:** A marginal distribution sums the frequencies across rows or columns to show totals for each category.
3. **Calculate row sums (marginal distribution for y):**
$$\text{Sum for } y_1 = 20 + 25 + 30 = 75$$
$$\text{Sum for } y_2 = 30 + 15 + 50 = 95$$
4. **Calculate column sums (marginal distribution for x):**
$$\text{Sum for } x_1 = 20 + 30 = 50$$
$$\text{Sum for } x_2 = 25 + 15 = 40$$
$$\text{Sum for } x_3 = 30 + 50 = 80$$
5. **Interpretation:** The marginal distribution for rows (y) is \(\{75, 95\}\) and for columns (x) is \(\{50, 40, 80\}\).
This means, for example, that the total frequency for category \(y_1\) is 75, and for \(x_3\) is 80.
**Final answer:**
- Marginal distribution for rows (y): \(y_1=75, y_2=95\)
- Marginal distribution for columns (x): \(x_1=50, x_2=40, x_3=80\)