Hello all,
I used Kruskal Wallis test to compare three data groups pra testar comparações em três grupos (b,c,s). The p-valor was < 0,05 in all cases (So, there is difference among at least two groups ). So, I compared pair the paires of groups (to know how groups are different) and it retruned FALSE in all comparisons oO.
> c = c(0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0);
> s = c(0,1,0,1,0,1,0,5,12,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,2,0,0,0,1,1,1,0,0,0,0,1,0,1);
> b = c(7,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0);
> kruskal.test(list(b,c,s));
Kruskal-Wallis rank sum test
data: list(b, c, s)
Kruskal-Wallis chi-squared = 12.0952, df = 2, p-value = 0.002364
> categ = factor(rep(1:3,c(20,40,40)),labels = c("g1","g2","g3"));
> data = c(b,c,s);
> kruskalmc(data,categ);
Multiple comparison test after Kruskal-Wallis
p.value: 0.05
Comparisons
obs.dif critical.dif difference
g1-g2 6.225 19.02047 FALSE
g1-g3 8.475 19.02047 FALSE
g2-g3 14.700 15.53015 FALSE
I didn´t understand those results. It is inconsistent. So, I used U Test with the objective of compare two groups of each time.
wilcox.test(b,c);
Wilcoxon rank sum test with continuity correction
data: b and c
W = 449.5, p-value = 0.07556
alternative hypothesis: true location shift is not equal to 0
Warning message:
cannot compute exact p-value with ties in: wilcox.test.default(b, c)
> wilcox.test(b,s);
Wilcoxon rank sum test with continuity correction
data: b and s
W = 332.5, p-value = 0.1742
alternative hypothesis: true location shift is not equal to 0
Warning message:
cannot compute exact p-value with ties in: wilcox.test.default(b, s)
> wilcox.test(c,s);
Wilcoxon rank sum test with continuity correction
data: c and s
W = 564.5, p-value = 0.0006209
alternative hypothesis: true location shift is not equal to 0
Like you can see, one of comparisons returned c and s groups are statically different. So, please, what can I conclude?
Thanks in advance!
I used Kruskal Wallis test to compare three data groups pra testar comparações em três grupos (b,c,s). The p-valor was < 0,05 in all cases (So, there is difference among at least two groups ). So, I compared pair the paires of groups (to know how groups are different) and it retruned FALSE in all comparisons oO.
> c = c(0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0);
> s = c(0,1,0,1,0,1,0,5,12,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,2,0,0,0,1,1,1,0,0,0,0,1,0,1);
> b = c(7,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0);
> kruskal.test(list(b,c,s));
Kruskal-Wallis rank sum test
data: list(b, c, s)
Kruskal-Wallis chi-squared = 12.0952, df = 2, p-value = 0.002364
> categ = factor(rep(1:3,c(20,40,40)),labels = c("g1","g2","g3"));
> data = c(b,c,s);
> kruskalmc(data,categ);
Multiple comparison test after Kruskal-Wallis
p.value: 0.05
Comparisons
obs.dif critical.dif difference
g1-g2 6.225 19.02047 FALSE
g1-g3 8.475 19.02047 FALSE
g2-g3 14.700 15.53015 FALSE
I didn´t understand those results. It is inconsistent. So, I used U Test with the objective of compare two groups of each time.
wilcox.test(b,c);
Wilcoxon rank sum test with continuity correction
data: b and c
W = 449.5, p-value = 0.07556
alternative hypothesis: true location shift is not equal to 0
Warning message:
cannot compute exact p-value with ties in: wilcox.test.default(b, c)
> wilcox.test(b,s);
Wilcoxon rank sum test with continuity correction
data: b and s
W = 332.5, p-value = 0.1742
alternative hypothesis: true location shift is not equal to 0
Warning message:
cannot compute exact p-value with ties in: wilcox.test.default(b, s)
> wilcox.test(c,s);
Wilcoxon rank sum test with continuity correction
data: c and s
W = 564.5, p-value = 0.0006209
alternative hypothesis: true location shift is not equal to 0
Like you can see, one of comparisons returned c and s groups are statically different. So, please, what can I conclude?
Thanks in advance!