Prove that, in a vickrey (second-price sealed-bid) auction, for any false bid bi by any single bidder (that is, if vi is the bidder's private value for the item, then bi≠vi), there exists a vector b−i of bids by all other bidders such that the false bid gives strictly worse utility than bidding the true valuation, that is, ui(bi, b−i)

Reliability and validity reliability and validity are two important considerations that must be made with any type of data collection. reliability refers to the ability to consistently produce a given result. in the context of psychological research, this would mean that any instruments or tools used to collect data do so in consistent, reproducible ways. unfortunately, being consistent in measurement does not necessarily mean that you have measured something correctly. to illustrate this concept, consider a kitchen scale that would be used to measure the weight of cereal that you eat in the morning. if the scale is not properly calibrated, it may consistently under- or overestimate the amount of cereal that’s being measured. while the scale is highly reliable in producing consistent results (e.g., the same amount of cereal poured onto the scale produces the same reading each time), those results are incorrect. this is where validity comes into play. validity refers to the extent to which a given instrument or tool accurately measures what it’s supposed to measure. while any valid measure is by necessity reliable, the reverse is not necessarily true. researchers strive to use instruments that are both highly reliable and valid.

You hold a diversified $100,000 portfolio consisting of 20 stocks with $5,000 invested in each. the portfolio's beta is 1.12. you plan to sell a stock with b = 0.90 and use the proceeds to buy a new stock with b = 1.50. what will the portfolio's new beta be? do not round your intermediate calculations.

Which of the following best explains the purpose of a strike? a. to pressure employers to increase the minimum wage. b. to make sure that producers don't make any profit. c. to get employers to submit to collective bargaining. d. to prevent employers from taking industrial action.