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The economist in Q1 was concerned about the confounding effe…

The economist in Q1 was concerned about the confounding effect on the treatment variable (i.e., prime_card variable); therefore, the economist applied the instrument variable (IV) method using two-stage least square regression (2SLS) to mitigate bias and get a consistent estimator for the treatment effect. In particular, randomly assigned eligibility of the prime membership card for consumers (i.e., ‘prime_elegible’) is used as an instrument variable (IV). we assume that ‘prime_elegible’ is a valid instrument variable (IV). Table 1 The empirical results from OLS Table 2 The empirical result from IV with 2SLS Based on the above Tables 1 and 2, the coefficient for the prime_card in OLS is (1)____________ (number, 1 point) and the coefficient of the prime_card (i.e., the predicted prime_card in the second stage) in 2SLS is (2)___________(number, 1 point). As a result, the OLS estimator may have (3)______________ (a. downward bias (i.e., underestimate), b. upward bias (i.e., overestimate); 2 points).      

These questions are related to design principles for secure…

These questions are related to design principles for secure systems. I. Consider a security screening setting like the one that is done at airports before travelers are allowed to board flights. Assume a certain airport uses the following screening protocols.1. Everyone, except those who are explicitly exempted, must undergo the security screening.2. All travelers go through the first screening stage. A subset of travelers are also flagged for a second screening.3. Once successfully screened, travelers only have access to the areas of the airport where their gates are located. What security design principle can be used to explain each of the above choices made for air travel security? Explain your answers. (2+2+2)II. The “Reflections on Trusting Trust” paper described a trojan in a compiler binary that could not be detected even if we had access to and examined the source of the compiler. We discussed how the defense-in-depth principle can help us detect if the trojan exists in a compiler by using two independently developed compilers when at least one of them is correct. We could determine if one of the compilers has the trojan but could not ascertain which one is malicious. To answer this question, the following idea is suggested. Instead of two, we will get three independently developed compilers such that no more than one could be malicious.1. If at least two of the compilers are good, can we use these three compilers to detect the bad one when one exists? (1 pts.)2. Explain your answer to question 2.1. More specifically, if your answer is no, explain why this is not possible. If the answer is yes, show how the bad compiler can be identified. (3 pts.)

David is a 7-year old boy who has been receiving occupationa…

David is a 7-year old boy who has been receiving occupational therapy services for 3 years in a school setting for a developmental delay. He is going to be re-evaluated for his eligibility for occupational therapy services in the educational setting during his triennial review (i.e., a re-evaluation that occurs every 3 years in schools for children with IEPs to determine eligibility for services). Which assessments are MOST appropriate to administer?