Which event from the 20th century best illustrates alexis de tocqueville's assertion that liberty was key to the united states' success as a constitutional republic? a. the united states periodically granted certain nations preferential trading status. b. the u. s. government exempted the amish, who do not believe in government assistance, from paying social security taxes. c. the environmental protection agency was founded in 1970 to monitor and protect natural resources. d. the united states was in the first group of nations to join the united nations when it was founded in 1945.

 B. The US government exempted the Amish, who do not believe in government assistance, from paying Social Security taxes.

Alexis de Tocqueville's concern for liberty had to do with personal liberties -- with freedom of conscience and belief being protected in a constitutional republic.  By respecting the rights of the Amish to exempt themselves from the Social Security system, the government of the United States is allowing them to have liberty of their beliefs.  They don't pay into the Social Security system, and also do not receive benefits from it.  They choose to care for themselves and one another in the Amish community.

Alexis de Tocqueville's famous work was published in the 1830s.  Based on his travels in the early United States, he wrote Democracy in America, in which he detailed how a democratic society functions.

the answer is b. i did this test and got it right.

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).