An Economist Conducted a Study of the Possible Association Between

question 26

Multiple Choice

An economist conducted a study of the possible association between weekly income and weekly grocery expenditures. Of particular interest was whether higher income would result in shoppers spending more on groceries. A random sample of shoppers at a local supermarket was obtained. A questionnaire was administered asking about the weekly income of each shopper's family and their grocery bill for that week. The scatterplot of weekly grocery expenditures vs. income shows:

• A)a weak positive association between the two variables.
• B)a weak negative association between the two variables.
• C)a strong positive association between the two variables.
• D)a strong negative association between the two variables.

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Definitions:

Discrete Probability

The mathematical study of probability where the outcome is determined from a set of distinct, separate values.

Queuing Theory

A body of knowledge about waiting lines.

Little's Law

A principle in queuing theory stating that the long-term average number of customers in a stable system L is equal to the long-term average effective arrival rate, λ, multiplied by the average time a customer spends in the system, W (L = λW).

Poisson Distribution

The Poisson Distribution is a statistical distribution that expresses the probability of a given number of events occurring in a fixed interval of time or space if these events occur with a known constant mean rate and independently of the time since the last event.