Question

The number of users of Facebook from 2004 through 2011 follows (Facebook website , April 16, 2012)

Year 2004 2005 2006 2007 2008 2009 2010 Period Users (Millions) 12 58 145 360 608 845 TA 4 acebook 2011 Construct a time series plot. What type of pattern exists? Using Minitab or Excel, develop a quadratic trend equation. a. b.

Answer 1

Part A: -

So the time series plot for the given data is shown below: -

Hence it is an exponentially increasing graph as shown above.

Part B: -

Now, excel can calculate regressions using both x¹ and x² at the same time:

Steps: -

1. Select the cell that contains your formula (as shown below)

2. Extend the selection the left 2 spaces (you need the select to be at least 3 cells wide)

3. Do the steps as mentioned below: -

Hence the solution will be: -

You will now see your 3 regression constants as shown above.

Hence the quadratic regression equation is: -

Y = 26.22024 X² - 116.351 X + 109.3393

Kindly note that the above process is applicable for Excel.