Bar Plot: How to Make It Online and Add It to Your Paper (APA7)
A bar plot shows one bar per category. For continuous outcomes the bar height is usually the group mean, with an error bar showing uncertainty.
What is Bar Plot?
A bar plot shows one bar per category. For continuous outcomes the bar height is usually the group mean, with an error bar showing uncertainty.
When to use it
Use a bar plot to compare group means or to show counts of categories. It is the standard chart for results from a t-test, ANOVA or chi-squared test.
Example question: Do the three teaching conditions differ in mean satisfaction?
Preparing your data
Long format works best: one row per participant, one column for the group and one column for the numeric outcome. For counts, one column with the category label is enough.
Example dataset (simulated; first rows of 90): condition (three teaching conditions), satisfaction (1 to 7 rating).
| condition | satisfaction |
|---|---|
| Lecture | 3.9 |
| Lecture | 5.4 |
| Lecture | 4.6 |
| Lecture | 5.1 |
| Lecture | 5.9 |
| Lecture | 5.1 |
Download the full example CSV to practise. If the tool asks for a different layout, follow the instructions on its page.
How to run it on StatFas
- Open the Bar Plot tool. You do not need an account to run an analysis.
- Enter your data or upload your file, laid out as described in Preparing your data.
- Select your variables. Choose the grouping variable for the x-axis and the numeric outcome for the y-axis. Pick the error bar type (standard deviation, standard error or 95% confidence interval).
- Choose any options the tool offers (for example the confidence level, a post hoc test or the error bar type) and run the analysis.
- Read the results on the page. Check the assumptions first, then the test statistic, the p-value and the effect size.
- To save your results, log in or create a free account. Every analysis stays free; the account is only needed to download.
Assumptions and checks
- A bar plot is a display, not a test, but it must start the y-axis at zero because the bar length encodes the value.
- State what the error bars show. A 95% confidence interval, a standard error and a standard deviation mean different things.
- With small groups, consider showing the individual data points as well as the bar.
- Use the same group order and colours across all figures in your paper.
Key numbers to look at
- Bar height: the mean (or count) for each category.
- Error bars: 95% confidence intervals that do not overlap suggest a difference, but overlap does not prove there is none.
- Axis labels with units and the scale range.
- Sample size per group, which belongs in the caption or the text.
Effect size
A figure does not report an effect size. Pair it with the test that compares the groups and report that test's effect size.
Benchmarks such as small, medium and large are conventions (Cohen, 1988), not rules. Interpret size in the context of your field.
Reporting Bar Plot in APA7 style
Template
Mean Satisfaction by Teaching Condition
[figure]
Note. Bars show means; error bars show 95% confidence intervals. n = XX per condition.
In the text: As shown in Figure 1, satisfaction was highest in the XX condition (M = X.XX, 95% CI [X.XX, X.XX]).
Worked example (simulated data)
The numbers below were computed from the example CSV above, so you can reproduce them. They illustrate the format and are not real findings.
| Condition | n | M | SD | 95% CI (bar and error bar) |
|---|---|---|---|---|
| Lecture | 30 | 4.79 | 1.00 | [4.42, 5.16] |
| Discussion | 30 | 5.43 | 0.81 | [5.13, 5.73] |
| Project-based | 30 | 5.64 | 0.84 | [5.32, 5.95] |
Figure caption (APA7 style)
Figure 1
Mean Satisfaction by Teaching Condition
Note. Bars show means; error bars show 95% confidence intervals. n = 30 per condition.
APA7 reminders: italicise statistical symbols (M, SD, t, F, p, r), report exact p-values to two or three decimals (use p < .001 for very small values), omit the leading zero for values that cannot exceed 1 (.45, not 0.45), and put degrees of freedom in parentheses. See the APA7 cheat sheet.
Common mistakes
- Truncating the y-axis so that small differences look large.
- Not stating what the error bars represent.
- Using a 3-D or heavily decorated chart; plain 2-D bars are clearest.
Related analyses and alternatives
- Line Graph: For values that change over time or across ordered steps.
- Pie Chart: For shares of a whole with only a few categories.
- One-way ANOVA: To test whether the bars differ.
Not sure which analysis you need? Use the test chooser.
Frequently asked questions
Which error bar should I use?
The 95% confidence interval is the most informative for comparing groups. If you use standard error bars, say so in the figure note.
Should the figure be black and white?
APA7 recommends figures that remain readable in grayscale. Use patterns or clearly different shades if your paper may be printed in black and white.
References
American Psychological Association. (2020). Publication manual of the American Psychological Association (7th ed.). https://doi.org/10.1037/0000165-000
This guide is for learning and for preparing results for your own reports. You remain responsible for choosing an appropriate analysis, checking its assumptions and interpreting the results. Follow the formatting rules of your journal or institution where they differ from APA7.