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Question
NARRBEGIN: SA_70_78A small grocery store has two checkout lines available to its customers: a regular checkout line and an express checkout line. Customers with 5 or fewer items are expected to use the express line. Let X and Y be the number of customers in the regular checkout line and the express checkout line, respectively. Note that these numbers include the customers being served, if any. The joint probability distribution of X and Y is given in the table below.
| Y = 0 | Y = 1 | Y = 2 |  3 | |
| X = 0 | 0.06 | 0.04 | 0.03 | 0.15 |
| X = 1 | 0.09 | 0.06 | 0.03 | 0.04 |
| X = 2 | 0.08 | 0.05 | 0.01 | 0.12 |
 3 | 0.07 | 0.05 | 0.03 | 0.09 |
Find the marginal distribution of Y. What does this distribution tell you?
Answer
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