Question

A special CPI is constructed to measure the variation of these products, so that coffee and bread have a weight of 0.35 of the total and egg, ham and cheese 0.1 of the total. variation of the CPI?

Answer 1

9514 1404 393

Answer:

The CPI increased 3.42% in Month 2.

Explanation:

In a spreadsheet, the weighted sum is easily computed using the SUMPRODUCT( ) function. It multiplies the corresponding values of two arrays, then returns the sum of those products. If one of the values is a weight, then the result is a weighted sum.

Your CPI is computed as the weighted sum of the prices of the individual products. The percentage change is computed in the usual way:

pct change = ((new value)/(old value) -1) × 100%

Of course, the spreadsheet can format a fraction as a percentage, so the computation of the change can stop after 1 is subtracted from the ratio.