I understand that PCA, the PC1 and PC2 explain the two most variances of data points in a dataset. Do we have any threshold for percentages of variances to conclude that the PC1 is 'good' or 'bad'? What is the relation of the percentage of variance with clustering?
In a particular case, if a dataset indicates that the 2 clusters clearly are separated with PC1 of ~20%)compared with 2 clusters that are not really separated but with PC1 of ~70%. Can we conclude that one is more trustable than the other?
Thanks for your help!