We will be considering linear, quadratic, cubic, logarithmic, or exponential models. Use your model to answer the questions that follow each problem, be sure to include units where applicable.
1) The table shows the number of people in North America who use email as a part of their jobs (Year, Email Users in millions)
(2005, 127.2), (2006, 130.7), (2007, 134.4), (2008, 138.0), (2009, 141.8), (2010, 145.6)
a) Find a model for the number of North American business email users given the number of years since 2005. (Be sure to align the data, that is let t = 0 correspond to 2005) Explain why a linear model seems most appropriate, include the model below.
b) According to the model what is the constant rate of change of the number of North American business email users? Include units in your explanation.
c) Use the model to estimate the number of North American business email users in 2013. Is this estimate found interpolation or extrapolation? Explain your answer.