Which graph displays the mean of a variable for each category, using bars?

Which graph displays the mean of a variable for each category, using bars?

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

Answer: (C)

Bar charts are used to compare a single numeric summary, like a mean, across different categories. Each category gets a bar whose height represents the average value, making it easy to see which category has the higher or lower mean at a glance. A line chart, on the other hand, connects data points to show a trend over ordered categories or time, not a direct comparison of means by category. A histogram conveys the distribution of one numeric variable by counting observations in value ranges, not averages per category. A scatter plot displays the relationship between two numeric variables or individual observations, not aggregated means by category. So using bars to show the mean for each category is the appropriate choice.

Bar charts are used to compare a single numeric summary, like a mean, across different categories. Each category gets a bar whose height represents the average value, making it easy to see which category has the higher or lower mean at a glance. A line chart, on the other hand, connects data points to show a trend over ordered categories or time, not a direct comparison of means by category. A histogram conveys the distribution of one numeric variable by counting observations in value ranges, not averages per category. A scatter plot displays the relationship between two numeric variables or individual observations, not aggregated means by category. So using bars to show the mean for each category is the appropriate choice.