Graphical Representation of Data

Introduction

• Presenter: Dr. Nick
• Topic: Understanding different types of graphs and their uses.

Purpose of Graphs

• Simplify the analysis of large data sets.
• Help identify patterns and answer questions.
• Aid in effective communication of findings.

Types of Graphs

1. Pictograph

• Description: Uses pictures or objects lined up in rows to represent data.
• Use Case: Best for categorical data; counting instances, not measurements.
• Example: Lining up fruit pieces to identify the most popular fruit.
• Variants: Data cards for individual data representation.

2. Bar Chart (Column Chart)

• Description: Uses the length/height of bars to represent frequency.
• Use Case: Suitable for categorical and some numerical data.
• Features: Easy to compare categories; can order by size for better insights.

3. Pie Chart

• Description: Circle divided into segments representing category proportions.
• Use Case: Only for categorical data with 5 or fewer categories.
• Cautions: Avoid 3D effects and 'exploding' segments.

4. Dot Plots

• Description: Each dot represents a data point, stacked for duplicate values.
• Use Case: Ideal for numerical data; visualizing distribution.
• Example: Number of shoes owned by individuals.

5. Stem and Leaf Plots

• Description: Combines aspects of a histogram and table.
• Use Case: Quick visual of data shape; uses first digit as 'stem' and second as 'leaf'.
• Example: Test scores.

6. Scatter Plot

• Description: Displays relationship between two numerical variables.
• Use Case: Does not join dots; useful for identifying correlations.
• Example: Relationship between Lego set size and price.

7. Time Series Plot

• Description: Special scatter plot for data over time.
• Use Case: Horizontal axis represents time; dots connected to show trends.
• Example: Monthly visitor data to New Zealand.

Conclusion

• Graph choice depends on context and investigation purpose.
• Sometimes multiple graphs are suitable.
• Statistical software can assist in creating appropriate graphs.

Additional Resources

• Visit the Statistics Learning Center website for more learning materials.