Learning Objectives
By the end of this lesson, learners should be able to:
- Define mean, median, and mode.
- Calculate measures of central tendency step by step.
- Interpret central tendency in business contexts.
- Select the most appropriate measure for different datasets.
Meaning Of Central Tendency
Measures of central tendency describe the typical or central value in a dataset. They provide a single number that represents the overall level of performance.
Why Managers Use Central Tendency
Managers use averages to:
- Estimate average customer spending,
- Compare regional sales,
- Set performance targets,
- Forecast staffing needs,
- Evaluate supplier performance.
Arithmetic Mean
The mean is the sum of all values divided by the number of observations.
Formula
Mean = Sum of values ÷ Number of observations
Worked Example
Monthly sales (USD thousands):
50, 60, 70, 80, 90
Step 1: Add the values
50 + 60 + 70 + 80 + 90 = 350
Step 2: Count observations
5
Step 3: Divide
350 ÷ 5 = 70
Interpretation
Average monthly sales are USD 70,000.
Business Meaning
If sales continue at this average level, annual sales are approximately USD 840,000.
Advantages And Limitations Of The Mean
Advantages
- Uses all observations,
- Easy to calculate,
- Suitable for further statistical analysis.
Limitations
- Highly affected by extreme values.
Median
The median is the middle value when data is arranged in order.
Example
Sales: 40, 50, 60, 70, 500
The middle value is 60.
Why Median Matters
The extremely high sale of 500 does not distort the median.
Business Interpretation
Typical customer spending is about USD 60,000, even though one customer spent much more.
Median is often preferred for:
- Income,
- Property prices,
- Customer spending,
- Executive compensation.
Mode
The mode is the most frequently occurring value.
Example
Delivery times (days):
2, 2, 3, 4, 4, 4, 5
Mode = 4 days.
Business Use
The mode identifies the most common customer experience.
A courier company may conclude that most deliveries arrive within four days.
Comparing Mean, Median, And Mode
|
Measure |
Best Use |
Sensitive to Outliers? |
|
Mean |
Symmetrical data |
Yes |
|
Median |
Skewed data |
No |
|
Mode |
Most common category/value |
No |
Skewness And Central Tendency
Symmetrical Distribution
Mean ≈ Median ≈ Mode.
Positively Skewed Distribution
Mean > Median.
Example: executive salaries.
Negatively Skewed Distribution
Mean < Median.
Example: customer satisfaction scores where most customers are highly satisfied.
Weighted Mean
Used when observations have different importance.
Example
|
Product |
Sales |
Weight |
|
A |
100 |
0.5 |
|
B |
80 |
0.3 |
|
C |
60 |
0.2 |
Weighted mean = (100×0.5) + (80×0.3) + (60×0.2) = 50 + 24 + 12 = 86
Interpretation
The weighted average sales score is 86, giving more importance to Product A.
Geometric Mean
Useful for growth rates.
Example
A company grows by:
- Year 1: +10%
- Year 2: +20%
- Year 3: +5%
The geometric mean provides the average annual growth rate and is widely used in finance and investment analysis.
International Business Case
A luxury retailer in Paris analyzes customer spending:
- Mean purchase = EUR 420
- Median purchase = EUR 180
Management concludes that a small number of very wealthy customers are inflating the average. Marketing campaigns are redesigned to target both premium customers and the broader customer base.
Common Mistakes
- Using the mean for highly skewed data.
- Ignoring outliers.
- Comparing means from datasets with different currencies.
- Reporting averages without sample size.
Practical Exercise
Calculate mean, median, and mode for monthly revenues from stores in London, Dubai, Singapore, Toronto, and Sydney, then explain which measure best represents typical performance.
Learning Materials / Reference Materials
- Newbold, Carlson & Thorne. Statistics for Business and Economics.
- OpenIntro Statistics.
- Excel AVERAGE, MEDIAN, MODE, and SUMPRODUCT documentation.
Lesson Summary
Measures of central tendency summarize the typical value in a dataset. Selecting the correct measure is essential for accurate business interpretation and decision-making.