Which graph plots a mean (or summary statistic) on the y-axis against a categorical variable on the x-axis, often with lines connecting category means?

Which graph plots a mean (or summary statistic) on the y-axis against a categorical variable on the x-axis, often with lines connecting category means?

• A. Bar chart
• B. Scatter plot
• C. Histogram
• D. Line chart

Answer: (D)

A line chart is used when you want to show how a summary statistic, like a mean, changes across categories on the x-axis. Plotting the mean for each category on the y-axis and connecting those category means with lines highlights any trend or pattern across the groups, which is exactly what this item describes. A bar chart would display the category means as bars without inherently linking them with lines. A scatter plot shows individual data points rather than a summary per category, and a histogram displays the distribution of a single variable rather than means across categories. So the line chart best fits the idea of plotting a mean by category with lines guiding the eye from one category to the next.

A line chart is used when you want to show how a summary statistic, like a mean, changes across categories on the x-axis. Plotting the mean for each category on the y-axis and connecting those category means with lines highlights any trend or pattern across the groups, which is exactly what this item describes. A bar chart would display the category means as bars without inherently linking them with lines. A scatter plot shows individual data points rather than a summary per category, and a histogram displays the distribution of a single variable rather than means across categories. So the line chart best fits the idea of plotting a mean by category with lines guiding the eye from one category to the next.