Similar to Oleg's answer, you could use the functions iqr and mean to address your first concerns. Note: interquartile uses median, not mean. For interquartile outlier output, use the 'quartiles' method for isoutlier. To get the same results between boxplot and isoutlier, make sure the whisker value in boxplot is the same value as the threshold factor in isoutlier.
load examgrades
t = datetime('2015-12-18 12:00:00') + days(1:120)';
g = grades(:,1);
figure
boxplot(g, 'Whisker', .5);
io = isoutlier(g,'quartiles','ThresholdFactor', .5);
outg = g(io);
outt = t(io);
t = table(outt, outg);
