We need to question whether the results of the regression in part (d) is revealing a causal relationship between concentration and airfares. In particular, we are concerned whether our estimation results on U. S. data are valid for other markets, such as Europe and Asia. Give one reason why the results would not be \externally valid" if applied to the airline industry in one of these other two regions.

Northern lights electronics just completed plans to distribute its new tablet. the product has several unique features that differentiate it from competitor products. the marketing team plans to begin a roll-out with to only one traditional retailer for the first two months. this strategy will give consumers the perception of the product’s stand-out personality and increase demand. marketing will proceed with for the next four months, where it plans to distribute to three other retailers, as well. for the last six months of the year, it will initiate distribution agreements with discount retailers and online retailers, and any other electronics store that wants to carry it. the marketing team is confident that the tablet will cycle through the first three stages of its product life cycle quickly. as the tablet reaches maturity during the second half of its first year in the market, it is good strategy to proceed with as described above. intensive distribution; selective distribution; exclusive distribution exclusive distribution; selective distribution; intensive distribution tertiary level distribution; secondary level distribution; mono-level distribution mono-level distribution; secondary level distribution; tertiary level distribution