13.33 AT&T wireline business.
With the continuing growth of the wireless phone market, it is interesting to study the impact on the wireline (landline) phone market. Consider a time series of the quarterly number of AT&T customers (in thousands) who have wireline voice connections.20 The series begins with the fourth quarter of 2011 and ends with the second quarter of 2014.
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13.33
(a) The number of wireline voice connections has been steadily decreasing over this time period. (b) There is no seasonal pattern. (c) . (d) The data appear to curve rather than follow a straight line.