Differential drop-out rates in your experimental and control groups (selection-attrition) is most likely to be a problem in which of the following designs: a. time series
b. regression discontinuity
c. pretest-posttest control group
d. nonequivalent comparison group

In what two ways were the tang and song dynasties of china similar? they jointly built the grand canal. they were economically strong. they had weak military forces. they ruled for about 300 years. they discouraged buddhist ideas.

“dear sir: it is with great reluctance, i trouble you on a subject, which does not fall within your province; but it is a subject that occasions me more distress, than i have felt, since the commencement of the war; and which loudly demands the most zealous exertions of every person of weight and authority, who is interested in the success of our affairs. i mean the present dreadful situation of the army for want of provisions, and the miserable prospects before us, with respect to futurity. it is more alarming than you will probably conceive, for, to form a just idea, it were necessary to be on the spot. for some days past, there has been little less, than a famine in camp. a part of the army has been a week, without any kind of flesh, and the rest for three or four days. naked and starving as they are, we cannot enough admire the incomparable patience and fidelity of the soldiery, that they have not been ere this excited by their sufferings, to a general mutiny or dispersion. strong symptoms, however, discontent have appeared in particular instances; and nothing but the most acitive efforts every where can long avert so shocking a catastrophe.” what’s the central idea?

In 1866, a mob in which tennessee city attacked local african americans and burned down homes and schools?