I suspect if you exchanged "religion" for "mystical supernatural beliefs not subject to proof" and there were no consequences for answering honestly, you'd find China trending closer to the centre; perhaps even to the right. It's a special case due to its history and government, so I'd discount its significance.
In any case, if the goal is to compare the happiness of societies (which is what Rakuen has claimed), how many people are in each society is technically irrelevant. It's like saying "are furries significantly happier than non-furries" – the answer doesn't rely on how many furries there are, as long as the sample is of a sufficient size to reach a conclusion at the given level of significance.
Of course, one could argue that no country is one society with one level of religiosity or happiness, any more than furries have a common level of happiness. But you have to draw a line somewhere, and countries are one convenient way to do so – especially if they have a state religion, as many do.
I agree that a country's GDP is likely to correlate to happiness, although higher discretionary income might correlate even better. (China has some areas which are prosperous, but many which are not.)
To be honest, I think the China data point is a misleading outlier, because:
I suspect if you exchanged "religion" for "mystical supernatural beliefs not subject to proof" and there were no consequences for answering honestly, you'd find China trending closer to the centre; perhaps even to the right. It's a special case due to its history and government, so I'd discount its significance.
In any case, if the goal is to compare the happiness of societies (which is what Rakuen has claimed), how many people are in each society is technically irrelevant. It's like saying "are furries significantly happier than non-furries" – the answer doesn't rely on how many furries there are, as long as the sample is of a sufficient size to reach a conclusion at the given level of significance.
Of course, one could argue that no country is one society with one level of religiosity or happiness, any more than furries have a common level of happiness. But you have to draw a line somewhere, and countries are one convenient way to do so – especially if they have a state religion, as many do.
I agree that a country's GDP is likely to correlate to happiness, although higher discretionary income might correlate even better. (China has some areas which are prosperous, but many which are not.)