In a recent study, Kramer et al. (2014) took a random sample of 320,000 Facebook users and divided them at random into two groups of 160,000 each. For one group (the experimental group) Kramer et al. altered their Facebook news feeds to reduce the number of news posts containing negative emotion words (e.g., sad, devastated, depressed, stressed, etc.) by 10%. That is, each of these 160,000 Facebook users saw 10% fewer negative words than usual. The other group of 160,000 participants (the control group) saw their usual, unaltered news feeds. Kramer et al. then measured the number of positive emotion words in posts made by each participant. The mean percentage of positive emotion words in the posts of the experimental group was mExp = 5.31%, with a standard deviation of SEXD = 4. For the control group the mean percentage of positive emotion words in these posts was mcontrol = 5.26%, with a standard deviation of SControl = 3. Please compute fobs based on mExp - mControl