The correct answer is D. Geometric mean.

Why “Geometric Mean” is the Most Appropriate Average for Averaging Price Relatives:

The geometric mean is considered the most appropriate average for averaging price relatives for several compelling reasons:

1. Multiplicative Relationships:

Price relatives represent changes in prices, and these changes often have a multiplicative relationship. When you multiply the price relatives together, you get the total percentage change in price over a series of time periods. The geometric mean is well-suited for handling such multiplicative relationships because it accounts for the compounding effect of changes.

2. Consistency with Percentage Changes:

The geometric mean aligns naturally with the concept of percentage changes, which is often how price relatives are interpreted. When you compute the geometric mean of a series of price relatives, you are essentially finding the average percentage change over time. This is useful for analyzing the overall trend in price movements.

3. Avoiding Biases:

Unlike some other means, such as the arithmetic mean, the geometric mean is not influenced by extreme values or outliers. This property is important when dealing with price relatives because extreme price fluctuations can have a disproportionate impact on other types of averages. The geometric mean provides a more balanced representation of overall price movements.

4. Preservation of Scale:

The geometric mean maintains the scale of the data. In the context of price relatives, this means that the geometric mean represents the same percentage change whether the prices are initially expressed in dollars, euros, or any other currency. This property is important for cross-country or cross-currency comparisons.

5. Useful for Investment Analysis:

The geometric mean is widely used in finance and investment analysis, where it helps calculate compound annual growth rates (CAGR). CAGR reflects the average annual rate of return or growth over a specified time period and is crucial for assessing the performance of investments or portfolios.

Price relatives are often used to compute CAGR, making the geometric mean a natural choice.

Why the Other Options Are Not Correct:

A. Median:

The median is not the most appropriate average for averaging price relatives because it does not account for the multiplicative nature of changes in prices.

A median is based on the middle value in a data set when values are arranged in ascending or descending order. It is more suited for handling data with additive relationships, where the values are not influenced by compounding effects.

B. Harmonic Mean:

The harmonic mean is not typically used for averaging price relatives because it tends to give more weight to smaller values. In the context of price relatives, this would mean that smaller price changes would have a disproportionately larger impact on the harmonic mean. This is not desirable when you want to capture the overall trend in price movements over time.

C. Arithmetic Mean:

While the arithmetic mean is a commonly used average, it is not the most appropriate choice for averaging price relatives. The arithmetic mean treats all values equally and calculates the average by summing the values and dividing by the number of data points.

However, this method is less suitable for price relatives because it does not reflect the multiplicative nature of price changes, and it can be heavily influenced by extreme values.

In summary, the geometric mean is the most appropriate average for averaging price relatives due to its ability to handle multiplicative relationships, its consistency with percentage changes, its resistance to biases from extreme values, its preservation of scale, and its relevance in investment analysis.

It provides a more accurate representation of the average rate of change in prices over time, making it a valuable tool for economic and financial analysis.