CMN 150V Final Exam questions and answers verified solutions| graded a+.

How much do some top celebs get paid per tweet? - correct answers $10,000 or more What are 2 complementary aspects of computational social science Lamberson talks about? - correct answers empirical work and computer simulations Are celebs the only people to have influence in society? - correct answers No Can just anybody be influential? - correct answers yes What trick did Lamberson use in order to track who reposted url link to a story on Twitter? - correct answers he tracked short url, which are unique to the post What are 'Twitter Cascades'? - correct answers an info diffusion process on Twitter in which a number of people make the same decision of passing along info in a sequential fashion Do all posts go viral? - correct answers the vast majority of posts never get retweeted, but a small fraction of links go viral If something went viral, looking at it, there is a high probability that it had 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? - correct answers low probability The proposed model consists of the following: - correct answers take a hypothetical network, select some nodes, and simulate a contagion process by assuming that neighboring nodes have a fixed probability of getting infected The horizontal x-axis presents: - correct answers if a given network(of simulated networks) has few or many links What determines what spreads or not? - correct answers density of network Even though we cannot predict who is influential, why is it worthwhile for companies to pay large amounts of money to celebs to send messages? - correct answers chances are that among the people reached by them, some turn out to be influential, who will the influence others What determines if an individual can trigger a cascade? - correct answers depends much more on the global structure of the influence network than it does on his or her personal degree on influence Can anyone start a cascade? - correct answers the overall network permits global cascades anyone can start one but if it doesnt then no one can What determines if someone is influential? - correct answers depends on the general structure of the network What is the difference between this lecture on social network analysis and the previous lectures on the same topic? - correct answers today, we will look at dynamically evolving networks and starts to simulate theoretical networks T or F? In science, things can be distributed in 4 diff ways: normal, poisson, exponential, powerlaw - correct answers false T or F? In science, things can be distributed in random, scale free, small world, hub/spoke networks - correct answers false What is one common way to scientifically test whether there's something special about your network? - correct answers you create a large number of random networks and compare your network with it Let's assume a very simple network with 3 nodes(A,B,C) and one (undirected) link: G(N,M) = G(3,1). How many different networks can you form with that? - correct answers 3 What was the differnece between the "numerical solutions" and "analytical solution"? - correct answers numerical: enumerate the options and basically count analytical: use math to derive the results In network analysis, a component is: - correct answers a part of the network in which a path can get you from a node to any other node Why do you need at least one connection per node in order for the giant component to dominate? - correct answers everybody can have one friend (on average) making a chain of friends Who will have more links? - correct answers older nodes What does preferential attachment mean? - correct answers the probability of a node to connect with new nodes corresponds to the number of existing degrees of a node What does preferential attachment say in this case? The probability that a new node: - correct answers connects to each one of them is equally likely What doe sit mean that something is distributed according to a power law? - correct answers exponentially few, have exponentially much, and exponentially many, have exponentially little Why are most of my friends connected to highly connected people? - correct answers popular people have many connection, inevitably also including my friends When you find a high clustering coefficient, it means that people group together in different densely connected clusters, what does that mean? - correct answers many people hang out with their groups with little connection to other groups What does it mean to have a small average path length? - correct answers the shortest path between all node sis short on average A small world network is characterized by - correct answers a small average path length and high clustering coefficient When social scientists say that societies consist of small world networks, what do they mean? - correct answers people have both close connections in tight groups and quick access to everybody What has benefits but also costs? - correct answers creating and maintaining links with others What is often meant when social scientists say that a dynamic social configuration has become stable? - correct answers nobody could benefit from changing anything in the configuration If there is almost no cost to create and maintain connection, what network will evolve? - correct answers a clique If there is a very high cost to create and maintain connections, what network will evolve? - correct answers a network without any links What is the average path length in a star network configuration(assume many nodes around a single hub)? - correct answers about 2 Why do (according to our model assumptions) indirect connects have benefits but no costs? - correct answers the lower left node still only needs to maintain one connection(to the upper left node), and maintaining connections are assumed to have costs How do we get 6 benefits and 6 costs? - correct answers there are 6 degrees(incoming/outgoing arrows) How many indirect benefits do we get now? - correct answers 6, two for each pair In the previous lecture, we said that this star configuration is the most efficient network structure for our network. However, besides all economic efficiency, what is the danger we just discovered? - correct answers -the network might not be stable, as some node might want to leave or change -the total social net efficiency is not fairly distributed among all members of society -since direct links are most costly than indirect links, some nodes benefit more than others 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? - correct answers -take away from the ones that have too much and give to the ones that have too little -redistribute resources until everybody is equally well off -use subsidies to balance costs and benefits among different of the network What was out definition of social stability? - correct answers nobody can improve the personal standing by modifying the existing social structure What was our definition of "social efficiency"? - correct answers the overall new benefit of it is maximized for the entire network Why do you need less steps to diffuse something in a scale free network compared to a random network? - correct answers hubs can reach many nodes very quickly What vaccination strategy would you suggest in a scale free preferential attachment network? - correct answers vaccinate the catalyzing central hubs If you ask some random members of a network to name a friend, is this friend more likely very popular or not? - correct answers on average, when asking many people, a popular person will be named more often Module 7 - correct answers When trying to understand an economy, the right "parts" to focus on are: - correct answers that depends on what you trying to understand Correct statements... - correct answers -lot of hares-num of lynx increases -lots of lynx-num of hares decrease -few hares-num of lynx decrease -few lynx-num of hares increase What do models not help us with? - correct answers they describe the world exactly as it is What do models help with? - correct answers -make us better thinkers -allows us to explore futures -allow clarify misunderstandings -explore forecast of uncertain futures All the rules followed by flocking birds in the model: - correct answers -avoid collision -be where others are -go where others go What are the 2 main assumptions of Axelrod's "cultural model"? - correct answers -people interact more likely with others who are similar -interactions cause one individual to change to match the other The percentage of similarity defines likelihood of interaction. If a person likes cats, top ramen, machine learning, cat memes and you like dogs, top ramen, sna, cat memes, what is the likelihood that you will interact? - correct answers 50% If "I" stands for liking and "O" for disliking, and 1st cultural feature represents "r & B" music, 2nd is dreadlocks, 3rd 49ers, 4th is FB: what could describe person C? - correct answers liking rb music, bald, dallas cowboys, just posted status update What does the color of these boundaries mean? - correct answers how similar people are to each other What will we explore today? How we can: - correct answers create theoretical models of societies that might not even exist in reality What is a model? - correct answers an idealized abstraction that represents something of interest What is something always involved in modeling? - correct answers omitting details and deciding which aspects to leave out If you find 2 completely different models that claim to model the same phenomena... - correct answers both of them can be useful, representing different aspects As we have just seen with example of London Tube Map, one ambition of modeling is often: - correct answers to be able to grasp the general gist behind an aspect of reality It is important to choose the right language to describe