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steven thomas: attempt 1
from 1910 to 1930, approximately 1.6 million migrants left rural areas in southern
states and moved to northern cities. this population shift was known as the great
migration.
which group relocated from the south to the north in the largest numbers during
this period?
native americans
mexican americans

the dissolution of the soviet union[a] occurred on december 26, 1991, officially granting self-governing independence to the republics of the soviet union. it was a result of the declaration number 142-н of the supreme soviet of the soviet union.[1] the declaration acknowledged the independence of the former soviet republics and created the commonwealth of independent states (cis), although five of the signatories ratified it much later or did not do so at all. on the previous day, december 25, soviet president mikhail gorbachev, the eighth and final leader of the soviet union, resigned, declared his office extinct, and handed over its powers – including control of the soviet nuclear missile launching codes – to russian president boris yeltsin. that evening at 7: 32 p.m., the soviet flag was lowered from the kremlin for the last time and replaced with the pre-revolutionary russian flag.[2]

previously, from august to december, all the individual republics, including russia itself, had either seceded from the union or at the very least denounced the treaty on the creation of the ussr. the week before formal dissolution, 11 republics signed the alma-ata protocol formally establishing the cis and declaring that the ussr had ceased to exist.[3][4] both the revolutions of 1989 and the dissolution of the ussr also marked the end of the cold war.

several of the former soviet republics have retained close links with the russian federation and formed multilateral organizations such as the commonwealth of independent states, eurasian economic community, the union state, the eurasian customs union, and the eurasian economic union to enhance economic and security cooperation. on the other hand, the baltic states have joined nato and th

a hypothesis is an expected answer to a question, usually based on some theory or prior research. hypothesis testing is a method of determining the viability of a hypothesis. let’s use the us presidential election as an example. there are many hypotheses (questions) about how people feel or whom they will vote for. the only way to know the 100% “truth” about the answers to these questions is to ask every single possible voter – something that is impossible, expensive, time consuming etc. instead, we take samples and use statistics to make “best guesses” about the answer to a particular hypothesis. we never know for sure if our conclusion is right at the time we accept/reject it, but these techniques, when used appropriately can get us close to the truth most of the time (which is a lot better than guessing, flipping coins or throwing darts to get answers).

the tricky part about hypothesis testing is that we have to think somewhat backwards about it – we have to test what is known as the “null hypothesis”. as an example, the hypothesis might be “obama is more popular than romney” while the null hypothesis is “there is no difference in popularity between obama and romney”. we focus on the null hypothesis because it tells us exactly what the expected value of our tests should be (obama popularity = romney popularity) and we can collect data and see if it comes out that way (see next section on “significance”). if it does, then we “accept the null hypothesis” and reject our original hypothesis. if the null hypothesis is disproven, we look at the data to see if our original hypothesis holds (obama> romney).