Question

For the past ten years, Michelle has been tracking the average annual rainfall in Boynton Beach, Florida by recording her data in the given table. She has concluded that the relationship can be modeled by a linear function.
Year 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
Average Rainfall (in inches) 62.33 61.8 61.27 60.74 60.21 59.68 59.15 58.62 58.09 57.56
Use the values provided in the table to create a linear model for the data. (Hint: Let x = 0 represent the year 2004). In your final answer, include all calculations necessary to create the model.
Assuming that the annual amount of rainfall continues to decrease at the same rate, use the linear model created in Part A to predict the rainfall in 2017.

Answer 1

Answer:

55.44 inches

Step-By-Step Explanation

part a. assuming a perfectly linear relationship, we can find the slope from the first two data points.

slope = m = (change in rainfall)/(change in years)

= (61.80 -62.33)/(2005 -2004) = -0.53/1 = -0.53

then the point-slope form of the equation of the line can be written as

y = m(x -h) +k . . . . . m = -0.53, (h, k) = (0, 62.33)

y = -0.53x +62.33 . . . x = years after 2004

part b. in 2017, x = 2017 -2004 = 13. then the predicted rainfall is

y = -0.53·13 +62.33 = 55.44 . . inches

the predicted rainfall in 2017 is 55.44 in