Listed below are the numbers of cell phone subscriptions (in thousands) in the United States for 11 recent years. Shown below the numbers are letters indicating whether the number is below (B) the mean or above (A) the mean, which is 63,526.2 thousand. Test for randomness of the numbers below and above the mean. Does there appear to be a trend?

use the runs test with a significance level of (All data are listed in order by row.)

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Year 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 Number 340 1231 3509 7557 16,009 33,786 55,312 86,047 128,375 158,722 207,900 B B В В В В В A A A A