Test significance

[mytechassist1]

A teacher wishes to test three different teaching methods I, II, III. To do this, the teacher chooses at random three groups of five students each and teaches each group by a different method. The same examination is then given to all the students and the marks obtained are given below. Determine at ?=0.05 significance level whether there is difference between the teaching methods. Use Kruskal-Wallis test.

Method I : 78-62-71-58-73
Method II: 76-85-77-90-87
Method III: 74-79-60-75-80

 

[royhaas]

Start by reading your textbook on how to use the Kruskal-Wallis test.

 

[mytechassist1]

Dear royhaas
Thanks for responding.

I already proceeded with the problem as follows:
1. I express the values in terms of ranks.
2. Compute the sum of ranks for each method separately ( they are 23, 59, 38 respectively).
3. Compute corresponding H test statistic. H is 6.54.
4. From the chi-square table, the critical value for ?=0.05 significance level with df = k-1 =2 is 5.991
From here we can conclude:
as 6.54 > 5.991, we reject the null hypothesis.

I can do the above thing. But the problem ask for some other thing. How can I compare the Three method so that I can decide the best one?
Please compute for me, if possible.

regds.
mytechassist1