The following six waves represent results of five different treatments (data2-data6) and a control (data1) to six objects (rows).

The Dunnett test compares the mean of each wave with that of the control. H₀ depends on the /TAIL flag which by default corresponds to testing equality of means. To run the test execute the command:

StatsDunnettTest/T=1/CIDX=0/TAIL=1  data1,data2,data3,data4,data5,data6

The results of the operation are displayed in Dunnett Test table:

In this case, we accept H₀, i.e., the mean value of the control wave (data1) is less than or equal to the mean values of waves: data3, data6, data4 and data5. To test H₀ corresponding to a control mean that is greater than or equal to other wave means execute the command:

StatsDunnettTest/T=1/CIDX=0/TAIL=2  data1,data2,data3,data4,data5,data6

The results are given again in the Dunnett Test table:

Inspecting the "Difference" column, we can see that the waves data3, data6 and data4 have mean values that are close to the mean value of the control wave the other two samples data2 and data5 are included or excluded in the group depending on the tail being tested. To run the two tail test execute the command:

StatsDunnettTest/T=1/CIDX=0/TAIL=4  data1,data2,data3,data4,data5,data6

The results are given again in the Dunnett Test table:

In this case we have a larger critical value which happens to accept the difference between the means of data1 and data2 but not data1 and data5.