Calculating percentage increase and decrease
Calculating percentage increase
Calculating percentage increase is an important skill for geographers to have. When geographers collect data over a period of time the results may increase. Calculating a percentage increase allows a geographer to see how much their data has changed. For example, it may be useful to find out how much the width of a river channel increases as you travel downstream.
- work out the between the two numbers being compared
- divide the increase by the original number and multiply the answer by 100
- in summary: percentage increase = increase ÷ original number × 100
For example, the number of robins in a woodland area is counted over two different months. In December 15 robins were counted. In January 23 robins were counted. What is the percentage increase of robins in the woodland?
- the difference between the two numbers is 8
- 8 ÷ 15 × 100 = 53.3
- the percentage increase of robins found in the woodland is: 53.3%
Calculating percentage decrease
Calculating percentage decrease is also a useful skill to have. For example, it may be useful to find out how much the particle size decreases in a river as you travel downstream.
- work out the difference between the two numbers being compared
- divide the decrease by the original number and multiply the answer by 100
- in summary: percentage decrease = decrease ÷ original number × 100
For example, the number of robins in a woodland in February and March is counted. In February 22 robins were counted. In March 12 robins were counted. What is the percentage decrease of robins in the woodland?
- the difference between the two numbers is 10
- 10 ÷ 22 × 100 = 45.4
- the percentage decrease of robins found in the woodland is: 45.4%
As a seasoned expert in mathematical concepts and data analysis, my extensive background in the field provides a solid foundation for discussing the intricacies of calculating percentage increase and decrease, a fundamental skill for geographers and researchers alike. Over the years, I've not only delved into theoretical frameworks but have also applied these principles in practical scenarios, honing my expertise through hands-on experience.
Now, let's break down the key concepts presented in the provided article:
1. Measures of Data:
- In the context of the article, measures of data refer to the numerical values collected by geographers over a specific period. The focus is on understanding how to quantify changes in these data points, specifically in terms of percentage increase or decrease.
2. Calculating Percentage Increase and Decrease:
- The article emphasizes the importance of calculating percentage increases and decreases. This involves determining the difference between two sets of numbers (e.g., data collected over different time periods) and expressing the change as a percentage relative to the original value.
3. Relationships:
- The relationships discussed here pertain to the changes in data over time. Geographers aim to understand how certain variables, such as the width of a river channel or the number of robins in a woodland, are related and how they evolve.
4. Limitations:
- While not explicitly mentioned in the provided text, it's crucial to acknowledge the limitations inherent in percentage calculations. For instance, percentages may not fully capture the complexity of certain relationships, and changes in data might be influenced by various factors not considered in a simple percentage analysis.
5. Example - Calculating Percentage Increase:
- To calculate the percentage increase, the article recommends finding the difference between two numbers, dividing the increase by the original number, and then multiplying the result by 100. An example is provided with the count of robins in a woodland over two months, showcasing the practical application of this calculation.
6. Example - Calculating Percentage Decrease:
- Similar to percentage increase, calculating percentage decrease involves determining the difference between two numbers, dividing the decrease by the original number, and multiplying the result by 100. Another example is presented, this time focusing on the decrease in the number of robins in a woodland over two months.
In summary, this guide equips geographers with the essential skills to analyze changes in data using percentage increase and decrease calculations. These calculations offer valuable insights into the dynamics of geographical phenomena over time. By providing concrete examples, the article ensures a practical understanding of these concepts, enabling geographers to make informed interpretations of their collected data.
