A survey of household expenditures shows the following changes over the same week in each of three years for an average family:
Item Unit Quantity Price
Purchased (N)
Year 1 Year 2 Year 3 Year 1 Year 2 Year 3
Sugar kg 4kg 6kg 2kg 120 128 150
Bread Loaf 4 10 15 100 120 180
Tea kg 0.5 1.2 3.0 60 65 90
Milk Pint 25 30 25 68 72 100
Butter kg 2 5 8 200 205 260
(a) Using year 1 as the base period, compute index numbers for years 2 and 3, using the Laspeyres method.
(b) State and explain whether a survey based on these items represents a reasonable assessment of changes in the cost of food over the three years.