CMN 150V Spring 2022 Final exam with all complete questions and answers solutions guaranteed|

$10,000 or more - correct answers How much do some top celebrities get paid per tweet? whenever something spreads somewhere, along the way, one "exceptional person" finds out about the trend, then everybody else gets on the trend - correct answers Malcolm Gladwell - The Tipping Point: "The law of the few" means... one american in 10 tells the others what to eat, what to wear, etc... - correct answers "The influentials" book says... from the media, to influencers, to the public - correct answers What does the "two-step flow model" say? Information flows: empirical work & computer simulations - correct answers What are the two complementary aspects of Computational Social Science Prof. Lamberson from UCLA will talk about? An information diffusion process on Twitter in which a number of people make the same decision of passing along information in a sequential fashion - correct answers What are 'Twitter cascades'? The vast majority of posts never get retweeted, but a small fraction of links go viral - correct answers What is the first thing researchers found when looking at the empirical evidence about Tweets that go viral? Training set & test set - correct answers Does this sound familiar? In a data science framework, what are the first and second part of the data refer to? Bottom left - correct answers If it turned out that one of the top-25 most retweeted URLs came from an account that had little influence in the past, and has a small number of followers, where would it be located in this graph? Mid-bottom - correct answers If it turned out that one of the top-25 most retweeted URLs came from an account that had MID-LEVEL influence in the past, and has a small number of followers, where would it be located in this graph? 1 in 2 million - correct answers Let's assume that if you have this disease, you will surely have these symptoms. Now, 1 in 6 million people have this disease. Let's assume that 1/3 of the population of 6 million people has these symptoms (2 of 6 million = more have symptoms than the disease). Imagine you are part of the group that has the symptoms. What's your chance of having the disease, given that you have the symptoms? 100% - correct answers Sticking to our previous example, we said that the probability p(disease | given the | symptoms) was 1/2,000,000 = 0.00005 % What had we assumed is the probability p(symptoms | given the | disease)? low probability - correct answers If something went viral, looking at it, there is a high probability that it has been sent by an influencer: p(influencer | viral) What about p(viral | influencer), the probability that something goes viral, given that it was sent by an influencer? Take a hypothetical network, select some nodes, and simulate a contagion process by assuming that neighboring nodes have a fixed probability of getting infected - correct answers The Prof. Lamberso's proposed model consists of the following: If a given network (of the simulated networks) has few or many links - correct answers The horizontal x-axis presents: the general structure of the network - correct answers What is the lesson learned here? Whether someone is influential depends on: Because chances are that among large number of people reached by them, some turn out to be influential, who will then influence others - correct answers Even though we cannot predict who is influential, why is it still worthwhile for companies to pay large amounts of money to celebrities to send out messages? Today we will look into dynamically evolving networks + start to simulate theoretical networks - correct answers What is the difference between this lecture on Social Network Analysis, and the previous lecture on the same topic? from Ancient Greek (homou, "together") and Greek (philia, "friendship") is the tendency of individuals to associate with similar others. - correct answers Homophily: context - correct answers In his lecture, Prof. Fowler from UCSD (UCCSS_Fowler_2: From Obesity to Generosity (7min)) presented a third possibility of why similar people add up together: contagion, homophily and: False - correct answers t/f: In science, things can be distributed in four different ways: normal distribution; Poisson distribution; exponential distribution; & powerlaw distribution. false - correct answers t/f: In science, networks can form in four different ways: random networks; scale-free networks; small world networks; hub&spoke / star network. the sum of the length of the shortest paths between the node and all other nodes in the graph - correct answers Closeness centrality is calculated as: You create a large number of random networks, and compare your network with it - correct answers What is one common way to scientifically test whether there's something special about your network? entities are connected to each other via multiple types of connections - correct answers Multiplex network: "who communicate" = "communication network""have...friends" = "friendship network""more friends" = "high degree centrality" - correct answers Look at this pseudo "theory" (on the left) and then at the "hypothesis" on the right. Can you see how the scientific hypothesis makes an informal verbal idea more concrete? What aspects are equivalent in this translation? (check all that apply) 3 - correct answers Let's assume a very simple network with three nodes (A, B, C) and one (undirected) link: G(n,M) = G(3,1). How many different networks can you form with that? ...draw three nodes and try it out... The number of possible G(3,2) is the same as all possible G(3,1) - correct answers Wait! I thought you can do 3 graphs with 3 nodes and 1 link! What's the connection here? For numerical solutions, you enumerate the options and basically count, for analytical solutions you use math to derive the results - correct answers Wait again! What was the difference between the "numerical solution" and the "analytical solution"? a part of the network in which a path can get you from a node to any other node - correct answers In network analysis, a component is: 3 - correct answers How many of the 50 people are in the "giant component" at this point (in the largest connected subgraph)? everybody can have one friend (on average), making a chain of friends - correct answers Why do you need at least 1 connection per node in order for the giant component to dominate? a walk that ends where it began - correct answers In network analysis, a cycle is: the probability of a node to connect with new nodes, corresponds to the number of existing degrees of a node - correct answers What does "preferential attachment" mean? connects to each one of them is equally likely - correct answers What does preferential attachment say in this case? The probability that a new node: exponentially few, have exponentially much, and exponentially many, have exponentially little - correct answers What does it mean that something is distributed according to a power-law? what fractions of my friends are friends - correct answers Informally speaking, triadic closure / clustering coefficient assesses: popular people have many connections, inevitably also including my friends - correct answers Why are most of my friends connected to highly connected people? six degrees of separation - correct answers What is the stylized factual concept about the number of degrees of separation in social systems? with the number of closed triangles - correct answers One of the characteristics of a small world network is a high clustering coefficient. How is that calculated again? = UCCSS_SNA1_11: Triangles (5min) many people hang with their groups, with little connection to other groups - correct answers When you find a high clustering coefficient, it means that people group together in different densely connected clusters, what does that mean? the shortest path between all nodes is short, on average - correct answers What does it mean to have a small average path length? a small average path length + a high clustering coefficient - correct answers A small world network is characterized by: people have both close connections in tight groups and quick access to everybody - correct answers When social scientists say that societies consists of small world networks, what do they mean? nobody could benefit from changing anything in the configuration - correct answers What is often meant when social scientists say that a dynamic social configuration has become stable? a clique - correct answers If there is almost no cost to create and maintain connections, what network will evolve? a "network" without any links - correct answers If there is a very high cost to create and maintain connections, what network will evolve? almost 2 - correct answers What is the average path length in a star network configuration (assume MANY nodes around a single hub)? 4 * 0.6 = 2.4 just in case you're interested why: 4*0.8 (benefits) - 4*0.2 (costs) = 4 * (0.8 - 0.2) = 4*0.6 - correct answers What is the aggregate net benefit for the entire network? (benefits - costs) ...no trick question: just calculate what you see on the screen... The lower left node still only needs to maintain one connection (to the upper left node), and maintaining connections are assumed to have costs - correct answers That's an important point (it will influence the entire efficiency and stability result): why do (according to our model assumptions) indirect connections have benefits but no costs? 0.8 * 0.8 (80% of 80%) = 0.64 (64%) - correct answers sidebar interaction. Press tab to begin. OK, wait: so the direct benefit of connecting to another node directly is 0.8 (let's say 80%). Now the indirect benefit, of going through another node to a third node (two steps of separation) is what? there are six degrees (incoming/outgoing arrows) - correct answers sidebar interaction. Press tab to begin. Why do we get "six benefits" and "six costs"? 6, two for each pair - correct answers sidebar interaction. Press tab to begin. How many indirect benefits do we get now? Decreased - correct answers Has the social efficiency (the total sum of the efficiency of all nodes/agents) increased or decreased with this last reconfiguration of the network? The total social net efficiency is not fairly distributed among all members of society The network might not be stable, as some nodes might want to leave or change Since direct links are more costly than indirect links, some nodes benefit more than othersThe total social net efficiency is not fairly distributed among all members of society - correct answers In the previous lecture ( Take away from the ones that have too much and give it to the ones that have too little Use subsidies to balance costs and benefits among different members of the network Redistribute resources until everybody is equally well off - correct answers Following the logic outlined here, if some members could still increase their status by changing the network, what could be done to stabilize the existing network structure? (check all that apply) Nobody can improve the personal standing by modifying the existing social structure - correct answers What was our definition of "social stability"? The overall net-benefit of is maximized for the entire network - correct answers What