To calculate the weighted price index, we will use the formula for the Laspeyres Price Index:
\( PI_L = \frac{\sum (P_1 \times Q_0)}{\sum (P_0 \times Q_0)} \times 100 \)
Where:
- \( P_0 \) is the price in the base year.
- \( P_1 \) is the price in the current year.
- \( Q_0 \) is the weight, acting as the quantity in the base year.
Using the provided data:
Variable | \( P_0 \) | \( P_1 \) | \( Q_0 \) |
---|
X | 30 | 50 | 8 |
Y | 10 | 15 | 7 |
Z | 25 | 30 | 4 |
Calculate the numerator \(\sum (P_1 \times Q_0)\):
\( (50 \times 8) + (15 \times 7) + (30 \times 4) = 400 + 105 + 120 = 625 \)
Calculate the denominator \(\sum (P_0 \times Q_0)\):
\( (30 \times 8) + (10 \times 7) + (25 \times 4) = 240 + 70 + 100 = 410 \)
Compute the Laspeyres Price Index:
\( PI_L = \frac{625}{410} \times 100 \approx 152.44 \)
Thus, the weighted price index number is:
152.44