[R] k- means cluster analysis

[Ngayee J Law]

Hi all,

I am trying to run the k-means cluster analysis using the function kmeans
in the package cluster.
The data are:
x = c(-0.26, -0.23, -0.05, -0.20,  0.30, -0.84, -0.10, -0.12,  0.10, -0.31,
-0.19,  0.18, -0.26,
      -0.23, -0.37, -0.23)
I've got two different solutions when I ran this function over a few times:
kmeans(x, centers=2)

The first solution gives the following:
$cluster
 [1] 2 2 1 2 1 2 2 2 1 2 2 1 2 2 2 2
$centers
        [,1]
1  0.1325000
2 -0.2783333
$withinss
[1] 0.0646750 0.4033667
$size
[1]  4 12

The second solution gives the following:
$cluster
 [1] 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1
$centers
        [,1]
1 -0.1313333
2 -0.8400000
$withinss
[1] 0.5035733 0.0000000
$size
[1] 15  1

I don't understand why this is happening, and how do I choose between the
two solutions. Also, how can I ensure
consistent solution over times? Thanks a lot!

- Jacqueline