Data available for download: The six first principal components computed from ERSST v3b in the JClim study (original M - set, 1910 - 2009) are available here. (mbari.org)
Each of the five groups differed significantly (P < 0.001) from the other groups by the first principal component (one - way ANOVA, with Tukey's post-hoc comparisons). (journals.plos.org)
I was interested to note this finding in the «Gathering Feedback» report (page 30): for all five classroom observation tools the team analyzed, «the first principal component was simply an equal - weighted average of all competencies.» (jaypgreene.com)