When considering the impact of individual consumption levels on a country's economic health, which segment of the population is the most important contributor?
a
the lower class, because there are so many of them
b
the upper class, because they consume higher-priced goods.
c
the upper class, because they pay the most taxes
d
the middle class, because they consume the most
e
all classes contribute equally to a country's economic health

In terms of the "great wheel of science", statistics are central to the research process (a) only between the hypothesis phase and the observation phase (b) only between the observation phase and the empirical generalization phase (c) only between the theory phase and the hypothesis phase (d) only between the empirical generalization phase and the theory phase

You have just been hired as a brand manager at kelsey-white, an american multinational consumer goods company. recently the firm invested in the development of k-w vision, a series of systems and processes that allow the use of up-to-date data and advanced analytics to drive informed decision making about k-w brands. it is 2018. the system is populated with 3 years of historical data. as brand manager for k-w’s blue laundry detergent, you are tasked to lead the brand's turnaround. use the vision platform to to develop your strategy and grow blue’s market share over the next 4 years.

Russell's study compared gpa of those students who volunteered for academic study skills training and those who did not elect to take the training. he found that those who had the training also had higher gpa. with which validity threat should russell be most concerned?