I have paired data with measurement of time in seconds for unstructured type (variable
clean_final_Unstructured_time_ID_only_aggregated_ordered$Time) and structured type (variable
First I calculate median differences:
(median_Unstructured_agreg <- median(clean_final_Unstructured_time_ID_only_aggregated_ordered$Time)) (median_Structured_agreg <-median(clean_final_Structured_time_ID_only_aggregated_ordered$Time)) median_Unstructured_agreg - median_Structured_agreg
> (median_Unstructured_agreg <- median(clean_final_Unstructured_time_ID_only_aggregated_ordered$Time))  219 > (median_Structured_agreg <-median(clean_final_Structured_time_ID_only_aggregated_ordered$Time))  319.5 > > median_Unstructured_agreg - median_Structured_agreg  -100.5 >
After I am conducting "Sign Test for Two-sample Paired Data" (as described here: https://rcompanion.org/handbook/F_07.html)
library(BSDA) SIGN.test(x = clean_final_Unstructured_time_ID_only_aggregated_ordered$Time, y = clean_final_Structured_time_ID_only_aggregated_ordered$Time, alternative = "two.sided", conf.level = 0.95)
Dependent-samples Sign-Test data: clean_final_Unstructured_time_ID_only_aggregated_ordered$Time and clean_final_Structured_time_ID_only_aggregated_ordered$Time S = 4, p-value = 0.1185 alternative hypothesis: true median difference is not equal to 0 95 percent confidence interval: -224.23839 38.26659 sample estimates: median of x-y -99 Achieved and Interpolated Confidence Intervals: Conf.Level L.E.pt U.E.pt Lower Achieved CI 0.8815 -211.5000 -32.0000 Interpolated CI 0.9500 -224.2384 38.2666 Upper Achieved CI 0.9648 -227.0000 53.5000
As I understand
median of x-y from my output is the same as "paired differences" from here: https://statistics.laerd.com/spss-tutorials/sign-test-using-spss-statistics.php and there they interpret that value as I understand difference of medians "The carbohydrate-protein drink elicited a statistically significant median increase in distance run (0.113 km) compared to the carbohydrate-only drink, p = .004."
Why the difference of two medians that I calculated
-100.5is different from BSDA R package
median of x-yvalue which is
-99? I understand that that is not much difference but anyway it is and I want to know why.
Can I present that median differences as effect size?