This sub-page of the Data Analysis page displays results of specific tests on the data values from the Data Entry Sub-page.
This page contains the following controls / displays:
Seasonal Kendall Estimate of Slope |
VSP calculates Seasonal Kendall estimate of the slope for the selected data values. |
VSP calculates the confidence interval on the non-parametric estimate of the slope. |
Linear Regression |
VSP conducts a least-squares linear regression on the selected data points in time. |
Seasonal Kendall Test |
VSP conducts the Seasonal Kendall (SK) test for monotonic trend for the selected data values. See the Seasonal Kendall design page for details on the SK test. |
Testing for Global Trends |
When all locations are selected from the Location Drop-list, a global trend test is conducted to see if trends differ by location or season. If trends differ by location then you should conduct Seasonal-Kendall tests for each location separately. If trends differ by season, then you should conduct a Mann-Kendall trend test for each season separately because the Seasonal-Kendall test results could be misleading. |
Homogeneity of Trends in Different Seasons |
When a single location is selected from the Location Drop-list, a homogeneity of trends test is conducted to see if trends differ by season. If trends differ by season, then you should conduct a Mann-Kendall trend test for each season separately because the Seasonal-Kendall test results could be misleading. |
Gilbert, R.O. 1987. Statistical Methods for Environmental Pollution Monitoring, Wiley, New York.