Apache OpenOffice (AOO) Bugzilla – Issue 63779
error in calculation coefficient of variation (graph)
Last modified: 2017-05-20 10:04:01 UTC
Mark an array, enter a "Kursdiagramm" and add the coefficent of variation (CV). The graph shows a line related to the points, the CV is indicated for all points. However, the CV are identical and calculted as the CV of the marked points which are taken for the line. The reason for this error seem to be that if you take columns for showing the point in the graph the CV is calculatd also along the columns and not row-wise and vice versa.
Created attachment 35367 [details] bug in graph presenting error bar charts
In order to visualize and check the error please add a number in the field below the graph data refs. See that a new point is added to the line and all CVs are updated to the CV of the whole column.
wrong component, changed to chart and re-assigned
What exactly is your problem? The variance is calculated for all values in the given range. The result is exactly one value, the variance. This same variance is displayed for all values, that's how it is supposed to work.
You are completely right, that the program calculates a variance of the whole data set and displays the variance of all data results for all data points by taking aech point as mean for the variance. The problem is that I don't know anyone who really needs this particular statistical graphics. The common requirements for data series are the following 1. you have a pool of data measured at one time point (such as in the column of the example) then you usually (if at all) show the points in one row. i.e. one !above! the other and add the calculated variance in the same row. 2. you have a set a data for different time points than you calculate the mean and variance or median and percentile for each time point and display the results along the time axis (such as in the graph of the example). In this case the the variance differs from time point to time point along the X-axis. You need such presentation for scientific data or the representation of stock values where you have a min/max or variance of the day or a time point of measurement and display it along the time axis 3. in case of a quality control chart you quantify the variance over all data of a time series but the representation of the variance is not displayed by taking each point as a mean showing the variance value for this point value but you show a two line band by taking the gobal mean (mean of all data points) and display each data point relative to this lines.
@akage: i change the type to enhancement.
Please attach example of the proposed behavior.
No info from author.