What are Error Bars?
Error bars are graphical representations of the variability of data. They are used on graphs to indicate the error or uncertainty in a reported measurement. In
histology, they help illustrate the range within which the true value lies, providing a visual indication of the precision and reliability of measured sample data.
Assess the
reliability of their results
Compare variability between different
tissue samples Identify potential outliers or anomalies
Make informed decisions based on the degree of
uncertainty in their measurements
Types of Error Bars
Several types of error bars can be used in histology, including: Standard Deviation (SD): Indicates the spread of the data points from the mean. It shows the variability within a single sample.
Standard Error of the Mean (SEM): Represents how far the sample mean is likely to be from the true population mean. SEM is usually smaller than SD and is useful when comparing means between different groups.
Confidence Intervals (CI): Provide a range within which the true value is expected to lie with a certain level of confidence, usually 95%. CI is particularly useful for indicating the reliability of an estimate.
If error bars overlap between two groups, it suggests that there is no significant difference between the groups.
If error bars do not overlap, it may indicate a statistically significant difference, although formal statistical tests are required to confirm this.
The length of the error bars gives an indication of the
precision of the measurement; shorter bars imply higher precision.
Common Mistakes When Using Error Bars
Error bars can be misinterpreted if not used correctly. Common mistakes include: Confusing SD with SEM: They represent different aspects of data variability and should be used appropriately.
Overinterpreting non-overlapping error bars: Non-overlapping bars suggest a difference, but it does not confirm statistical significance without proper testing.
Ignoring the sample size: Smaller sample sizes typically have larger error bars due to higher variability.
Best Practices for Using Error Bars in Histology
To ensure accurate and meaningful representation of data, consider these best practices: Clearly state what type of error bars are being used (SD, SEM, or CI).
Use error bars consistently across all graphs in a study.
Complement error bar representations with appropriate
statistical analyses to confirm findings.
Ensure the sample size is adequate to provide reliable results.
