I have no idea what q values are. Please help. Below is the data:

10mg 1, 2, 3

20mg 3, 5, 7

30mg 11, 13, 18

40mg 13, 17, 25

Assume that the different dose of a drug has a significant effect on memory. Perform a Tukey post hoc analysis to find out whether taking 20 mg of the drug will have a significantly different effect from taking 30mg of the drug. Only compare the groups that were given in this question.

And then the questions are:

1) computer the q-obtained value(s)

2) find the q-critical value, specific the information that you used in finding the q critical value

3) draw a conclusion

Please assist, thank you!