statistician44.bsky.social
@statistician44.bsky.social
If you have any concerns regarding the analyses, please feel free to request the output files. If a grouped median was calculated, it would certainly be present in the results.
April 13, 2025 at 5:46 PM
Furthermore, percentiles such as Q1 and Q3 are not always the focus of interpretation in ordinal or grouped data, as they are generally considered secondary summary measures compared to the median. This may explain why interpolated versions were not calculated or reported in this case.
April 13, 2025 at 5:41 PM
In standard statistical software such as SPSS, Q1 and Q3 are often calculated using the “discrete method” based on positional values in ordered data, rather than using grouped or interpolated estimates. This often results in Q1 and Q3 values being integers or ending in .5.
April 13, 2025 at 5:40 PM
The likely reason Q1 and Q3 appear as whole numbers or end in .5 while Q2 (the median) has a fractional component is due to the computation method.
April 13, 2025 at 5:40 PM
Rosner, B. (2015). Fundamentals of Biostatistics (8th ed., pp. 55–56). Cengage Learning.

Gravetter, F. J., & Wallnau, L. B. (2016). Statistics for the Behavioral Sciences (10th ed., pp. 78–80). Pearson.

Gupta, S. C. (2014). Fundamentals of Statistics (7th ed.). Himalaya Publishing.
April 13, 2025 at 5:20 AM
This method is widely supported in statistical literature and is implemented in standard statistical software packages, including SPSS. Several authoritative sources explain both the rationale and the procedure for grouped median computation:
April 13, 2025 at 5:20 AM
In grouped data, the median is not simply the middle score but an estimated value derived from cumulative frequencies within a defined class interval. This process leads to fractional results, especially when the data are skewed or asymmetrically distributed.
April 13, 2025 at 5:19 AM
Yes, grouped median values can indeed have decimal (fractional) components, and this is a natural result of the interpolation method used in their calculation.
April 13, 2025 at 5:19 AM
We frequently encounter such situations in our analyses and often report grouped median values. It is highly likely that the researcher in this case followed the same approach to enhance interpretability.
April 12, 2025 at 12:31 PM
Otherwise, even if the medians are the same, differences in distribution might exist, requiring additional analyses such as distribution width, mode, or interquartile range to explain the findings accurately.
April 12, 2025 at 12:31 PM
Grouped median highlights the class in which the data are most concentrated, providing a central tendency measure based not only on position but also on frequency. This approach supports clearer interpretation, especially with limited-scale response formats.
April 12, 2025 at 12:31 PM
This inconsistency makes interpretation difficult for researchers. In such cases, using the grouped median offers a more informative summary of the data and better represents the concentration of responses across the scale.
April 12, 2025 at 12:30 PM
This limitation may lead to situations where the p-value shows statistical significance between two groups, yet the median values remain the same. In such cases, a perceived inconsistency emerges between statistical significance and the measure of central tendency.
April 12, 2025 at 12:30 PM
Likert-type data, due to their ordinal nature, can present challenges in the use of the median as a measure of central tendency. Since these data do not include decimal values, the median often falls within a limited range—typically 0 or 0.5.
April 12, 2025 at 12:30 PM