Problem

BUSINESS: Satellite Radio Subscribers The number of satellite radio subscribers in the U.S...

BUSINESS: Satellite Radio Subscribers The number of satellite radio subscribers in the U.S. for recent quarters is shown in the following table.

Year Quarter	2005 Q1	2005 Q2	2005 Q3	2005 Q4	2006 Q1	2006 Q2	2006 Q3	2006 Q4
Subscribers (millions)	2.2	6.3	7.2	9.1	10.4	11.5	12.1	13.8

a. Number the data columns with x-values 1–8 and use linear regression to fit a line to the data. State the regression formula. [Hint: See Example 8.]
b. Interpret the slope of the line. From your answer, what is the yearly increase?
c. Use the regression line to predict the number of satellite radio subscribers in the 4th quarter of 2010.

Source: Standard & Poor’s Industry Surveys

Example 8 LINEAR REGRESSION USNG A GRAPHING CALCULATOR