Standard Error (Score 1)

If you call the poll answers 0 for "not online" and 1 for "online", standard error can be calculated easily. First, standard deviation = square root of [mean of squares - square of mean]; both 0 and 1 are identities under squaring, so the mean of the squares is the same as the mean. So, stddev = sqrt(0.67 - 0.67^2) = 0.470. Standard error is calculated by dividing this by the square root of the number of samples; 0.470/sqrt(6403) = 0.00588.

That's an error of +-0.59% for both percentages, making the difference between 66% and 68% even less significant. The fact that only two digits of them are presented adds another +-0.5% error for both values, in a flat distribution. I don't know how to calculate the resultant significance, but it's pretty damned negligible.

If I've made an error, someone please correct me.