I am going through the 2 way anova steps provided by minitab. But I just can't get the answer for SE Mean as shown in this website (http://support.minitab.com/en-us/minitab-express/1/help-and-how-to/modeling-statistics/anova/how-to/two-way-anova/interpret-the-results/key-results/). Can I ask how is it calculated ? I use the normal equation (standard deviation divided by square root of number of sampels) but I can't get the answer as shown there. Thanks for the answer in advance.