Business Statistics

Learning Objective: Interpret business data using statistical methods

When Nepal Rastra Bank reports that inflation rose from 5% to 7%, or when a newspaper shows that tourist arrivals increased by 20%, they are using statistics. Business statistics helps managers make data-driven decisions by organizing, analyzing, and interpreting numerical information.

Index Numbers

An index number is a statistical measure that shows the change in a variable (price, quantity, or value) over time, compared to a base year.

Formula: Price Index = (Price in Current Year / Price in Base Year) x 100

Worked Example

Suppose the price of rice was Rs. 50/kg in 2075 BS (base year) and Rs. 70/kg in 2081 BS.

Price Index = (70 / 50) x 100 = 140

This means the price of rice increased by 40% compared to the base year.

Uses of Index Numbers:

• Nepal Rastra Bank uses the Consumer Price Index (CPI) to measure inflation
• The Nepal Stock Exchange (NEPSE) Index tracks overall stock market performance
• Wholesale Price Index helps monitor commodity prices

Time Series Analysis

A time series is data collected at regular intervals over time. It helps identify trends and patterns.

Components of a Time Series:

1. Trend (T): Long-term movement (upward, downward, or stable). Example: Nepal's GDP has an upward trend over the past decade.
2. Seasonal Variation (S): Regular fluctuations based on seasons. Example: Hotel bookings in Pokhara peak during October-November (tourist season).
3. Cyclical Variation (C): Fluctuations over several years due to business cycles (boom, recession).
4. Irregular Variation (I): Unpredictable changes due to unexpected events (earthquakes, pandemics).

Example: Tourist Arrivals in Nepal (Trend)

| Year (BS) | Arrivals (thousands) | Trend | |-----------|---------------------|-------| | 2074 | 740 | Increasing | | 2075 | 1,173 | Increasing | | 2076 | 1,197 | Stable | | 2077 | 230 | Sharp drop (COVID-19) | | 2078 | 150 | Low (pandemic) | | 2079 | 614 | Recovery |

Correlation

Correlation measures the relationship between two variables -- whether they move together or in opposite directions.

Types:

• Positive correlation: Both variables increase together. Example: As advertising spending increases, sales tend to increase.
• Negative correlation: One increases while the other decreases. Example: As the price of a product increases, demand tends to decrease.
• No correlation: No relationship between variables. Example: Shoe size and exam marks.

The correlation coefficient (r) ranges from -1 to +1:

• r = +1: Perfect positive correlation
• r = -1: Perfect negative correlation
• r = 0: No correlation

Data Interpretation

Business managers must read and interpret data presented in tables, graphs, and charts.

Tips for data interpretation:

• Always check the units and time period
• Look for trends (increasing, decreasing, stable)
• Compare percentages, not just absolute numbers
• Be aware of misleading graphs (truncated axes, exaggerated scales)

Key Term: The Consumer Price Index (CPI) measures the average change in prices paid by consumers for a basket of goods and services over time. It is the main indicator of inflation in Nepal.

Summary

• Index numbers measure changes in prices, quantities, or values relative to a base year.
• Time series analysis identifies trends, seasonal patterns, and cyclical changes in data.
• Correlation measures the strength and direction of the relationship between two variables.
• Good data interpretation requires checking units, identifying trends, and being wary of misleading presentations.