Questions
~2 questions per paper
Difficulty
Easy
Importance
High scoring, high-frequency basic math section
Overview
Data handling is the foundational study of representing and interpreting information through visual diagrams and statistical averages. In teaching recruitment exams, it tests your ability to extract specific insights from visual data and perform basic central tendency calculations, which are essential for classroom-based assessment analysis. Mastery of this topic ensures quick, marks-guaranteed scoring through systematic observation and calculation.
Bar Graphs
Bar graphs represent categorical data using rectangular bars where the length or height is proportional to the value represented. In exam contexts, you are usually expected to compare values across categories or calculate percentage changes between two data points.
- Bars can be oriented vertically or horizontally
- The X-axis usually represents categories, while the Y-axis represents frequency or magnitude
- Always check the scale provided on the Y-axis carefully
- Percentage increase = ((New Value - Old Value) / Old Value) * 100
Pie Charts
A pie chart displays data as slices of a circle, where the total area of the circle represents 100% or 360 degrees. To solve these, you often need to convert between percentages and absolute values or map percentages to degrees.
- 100% of the circle equals 360 degrees
- 1% is equivalent to 3.6 degrees
- Sum of all central angles must equal 360 degrees
- Value of a slice = (Percentage / 100) * Total Data Value
Mean, Median, and Mode
These measures define the central tendency of a dataset, summarizing the 'typical' value of a group. Understanding the distinct calculation methods for each is vital for solving basic statistical word problems.
- Mean (Average) = Sum of observations / Number of observations
- Median is the middle value in an ordered dataset
- If n is odd, Median = value at position (n+1)/2
- If n is even, Median = average of values at positions n/2 and (n/2 + 1)
- Mode is the observation that occurs with the highest frequency
Formula Sheet
Mean = Σx / n
Degrees = (Percentage / 100) * 360
Percentage = (Degrees / 360) * 100
Exam Tip
When working with pie charts, always convert the total value to 360 degrees first if the question asks for angle calculations, rather than calculating percentages then converting.
Common Mistakes
- Mixing up the conversion ratio between percentages and degrees in pie charts
- Failing to sort the dataset in ascending order before calculating the median
- Misreading the scale intervals on a bar graph, leading to incorrect absolute value extraction
More Revision Notes
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