Selection bias occurs when the association between exposure and health outcome is different for those who complete a study compared with those who are in the target population. Sources of selection bias. Selective survival and losses to follow-up After enrollment of subjects and collection of baseline data there is
NUMBER OF PUBLIC PHOTOS UPLOADED IN 2013. - 680 million, - 56.7 million per month in average, - 1.86 million per day in average. NUMBER OF PUBLIC PHOTOS UPLOADED IN 2012. - 556 million, - 46.3 million per month in average, - 1.52 million per day in average. NUMBER OF PUBLIC PHOTOS UPLOADED IN 2011. - 575 million, - 47.9 million per month in average, - 1.57 million per day in average.
Key research for how often to post to social media. 1  Twitter â 3 times per day, or more. 2  Facebook â 2 times per day, at most. 3  LinkedIn â 1 time per day.  Google+ â 3 times per day, at 1  most. Pinterest â 5x per day, or more.  Instagram â 1.5 times per day, or 1  more. Blog â 2x per  week.