Correlations for all pairs of data series (method=pearson)
	totsize	logins	tothyperlinks	feedback_messages_p120	totseconds(tekstverwerker)	compendiums_reviewed
totsize	1	-0.153	-0.126	-0.164	0.733	0.247
logins	-0.153	1	-0.012	0.998	-0.147	0.678
tothyperlinks	-0.126	-0.012	1	-0.013	-0.114	0.194
feedback_messages_p120	-0.164	0.998	-0.013	1	-0.159	0.678
totseconds(tekstverwerker)	0.733	-0.147	-0.114	-0.159	1	0.257
compendiums_reviewed	0.247	0.678	0.194	0.678	0.257	1

Correlations for all pairs of data series with p-values
pair	Pearson r	Spearman rho	Kendall tau
totsize;logins	-0.1528	0.4633	0.3288
p-value	(0.0546)	(0)	(0)
totsize;tothyperlinks	-0.1257	0.6758	0.5286
p-value	(0.1144)	(0)	(0)
totsize;feedback_messages_p120	-0.1641	0.5411	0.4035
p-value	(0.0388)	(0)	(0)
totsize;totseconds(tekstverwerker)	0.7325	0.7083	0.5394
p-value	(0)	(0)	(0)
totsize;compendiums_reviewed	0.2467	0.3814	0.2825
p-value	(0.0017)	(0)	(0)
logins;tothyperlinks	-0.0116	0.5413	0.3945
p-value	(0.8847)	(0)	(0)
logins;feedback_messages_p120	0.9976	0.4529	0.3303
p-value	(0)	(0)	(0)
logins;totseconds(tekstverwerker)	-0.1469	0.5811	0.4297
p-value	(0.0647)	(0)	(0)
logins;compendiums_reviewed	0.6781	0.5072	0.3682
p-value	(0)	(0)	(0)
tothyperlinks;feedback_messages_p120	-0.0127	0.509	0.3814
p-value	(0.8734)	(0)	(0)
tothyperlinks;totseconds(tekstverwerker)	-0.114	0.7803	0.6256
p-value	(0.1524)	(0)	(0)
tothyperlinks;compendiums_reviewed	0.1936	0.4976	0.3741
p-value	(0.0145)	(0)	(0)
feedback_messages_p120;totseconds(tekstverwerker)	-0.1588	0.48	0.352
p-value	(0.0456)	(0)	(0)
feedback_messages_p120;compendiums_reviewed	0.6777	0.7869	0.6541
p-value	(0)	(0)	(0)
totseconds(tekstverwerker);compendiums_reviewed	0.2575	0.4128	0.306
p-value	(0.0011)	(0)	(0)