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.
A surprising number of new photos are also posted in the first six hours of the day, with nearly 30 percent of posts landing before you even hit snooze. Now that there are more than 400 million people on Instagram, timing your post can do a lot to make sure friends and family see it. And brands will value the data too. While Instagram has recently opened up advertisements to just about any brand, companies can get some free marketing by just posting at the right times.