Study Notes
Methods of analysing data involve understanding different types of data and calculating measures like mean, median, mode, range, and quartiles to interpret and compare data sets.
- Raw Data — data collected from experiments or investigations, often unorganized. Example: Results from a survey before sorting.
- Discrete Data — data with specific, distinct values. Example: Number of students in a class.
- Continuous Data — data derived from measurements, can take any value within a range. Example: Height of students.
- Mean — sum of all data points divided by the number of points. Example: (11 + 12 + 14 + 10 + 16) / 5 = 12.6
- Mode — the most frequently occurring data point. Example: In 10, 4, 12, 2, 4, 11, 13, 2, 4, the mode is 4.
- Median — the middle value when data is ordered. Example: In 2, 5, 9, 12, 13, 15, 18, 20, 21, 22, 22, 25, 28, the median is 18.
- Range — difference between the largest and smallest values. Example: In 11, 7, 11, 18, 5, 6, 4, 16, 23, the range is 19.
- Interquartile Range — difference between the upper quartile (Q3) and lower quartile (Q1). Example: If Q3 is 75 and Q1 is 25, the interquartile range is 50.
Exam Tips
Key Definitions to Remember
- Raw Data: Unorganized data collected from experiments.
- Discrete Data: Data with specific values.
- Continuous Data: Data that can take any value within a range.
- Mean: Average of data points.
- Mode: Most frequent data point.
- Median: Middle value in ordered data.
- Range: Difference between largest and smallest values.
- Interquartile Range: Difference between Q3 and Q1.
Common Confusions
- Confusing mean with median.
- Misidentifying the mode in a data set.
- Forgetting to order data before finding the median.
Typical Exam Questions
- What is the mean of this data set? Add all values and divide by the number of values.
- How do you find the median of a data set? Order the data and find the middle value.
- What is the mode of this data set? Identify the most frequently occurring value.
What Examiners Usually Test
- Ability to calculate mean, median, and mode.
- Understanding of how to find the range and interquartile range.
- Interpretation of data using these statistical measures.