1. An indicator of inefficiency in a single server (multiple single lines each with its own server) queue system is: a. having idle servers. b. having waiting customers. c. having idle servers and waiting for customers at the same time. d. having idle servers or waiting customers.

2. A few years ago, Google found a significant correlation between online searches on Google about flu and actual flu spread figures - and used that knowledge to build a forecast for flu spread that beat the CDC's forecast. However, the following years forecasts made by Google, using similar search data from those years, were off by a significant margin (overforecasted). Why did this most likely happen?

a. Because increased awareness of flu in the general public led many more to take flu shots, and thus the incidence of flu was lower than forecasted

b. Because the gradual increased awareness of flu in the general public led to increased Google searches by healthy people - who did not eventually catch the flu. As such, the correlation between the # of Google searches and the actual flu cases that happened after the searches, declined considerably. Google's forecasts were presumably still running based on the earlier, stronger, correlation.

c.Because the flu strains change drastically from year to year, and thus the actual spread of the disease declined radically because a weaker flu strain came in the years following Google's first forecast.