Learner can choose the right chart type (line, bar, scatter, histogram, pie) for a given analytical question.
Five chart types and when to use them
Five chart types and when to use them
Choosing the wrong chart type makes correct data look confusing or misleading. Each chart type answers a specific kind of question.
Line chart — use it when you want to show how a value changes over time (a trend). The x-axis is always a time dimension: days, months, years. Example question: "How did our weekly sales change over the past six months?"
Bar chart — use it when you want to compare a numeric value across different categories. Each bar represents one category. The y-axis must start at zero so bar heights are proportional. Example question: "Which city generated the most revenue last quarter?" Scatter plot — use it when you want to explore the relationship between two continuous numeric variables. Each point is one observation plotted by (x, y). Example question: "Is there a relationship between advertising spend and sales volume?"
Histogram — use it when you want to see how one continuous variable is distributed across a range: how many observations fall in each bucket? It looks like a bar chart but the x-axis is a numeric range, not categories. Example question: "How are delivery times distributed — are most orders fast, or is there a long tail of slow ones?" Pie chart — use it sparingly. It shows parts of a whole (shares that sum to 100 %). It works only for simple compositions with a small number of slices and should never be used to compare values across categories or over time. Example question: "What share of total revenue comes from each of our three product lines?"
Lesson notes
Five chart types and when to use them
Choosing the wrong chart type makes correct data look confusing or misleading. Each chart type answers a specific kind of question.
Line chart — use it when you want to show how a value changes over time (a trend). The x-axis is always a time dimension: days, months, years. Example question: "How did our weekly sales change over the past six months?"
Bar chart — use it when you want to compare a numeric value across different categories. Each bar represents one category. The y-axis must start at zero so bar heights are proportional. Example question: "Which city generated the most revenue last quarter?" Scatter plot — use it when you want to explore the relationship between two continuous numeric variables. Each point is one observation plotted by (x, y). Example question: "Is there a relationship between advertising spend and sales volume?"
Histogram — use it when you want to see how one continuous variable is distributed across a range: how many observations fall in each bucket? It looks like a bar chart but the x-axis is a numeric range, not categories. Example question: "How are delivery times distributed — are most orders fast, or is there a long tail of slow ones?" Pie chart — use it sparingly. It shows parts of a whole (shares that sum to 100 %). It works only for simple compositions with a small number of slices and should never be used to compare values across categories or over time. Example question: "What share of total revenue comes from each of our three product lines?"