Some corrections Liang He, University of Helsinki 31 March 2015 In the last line of the expressions (2), αβ2 should have been σβ2. The second equation in the expression (5) should have been deleted. In the expression (6), 'y' is better replaced by 'Data'. In the footnotes of Table 1, '(2)' should have been '(5)', and '(3)' should have been '(6)'. Competing interests None declared
Some corrections
31 March 2015
In the last line of the expressions (2), αβ2 should have been σβ2.
The second equation in the expression (5) should have been deleted.
In the expression (6), 'y' is better replaced by 'Data'.
In the footnotes of Table 1, '(2)' should have been '(5)', and '(3)' should have been '(6)'.
Competing interests
None declared