Three years of monthly lawn-maintenance expenses ($) for a six-unit apartment house insouthern Florida follow.Month Year 1 Year 2 Year 3January XXXXXXXXXX195February XXXXXXXXXX210March...

Three years of monthly lawn-maintenance expenses ($) for a six-unit apartment house insouthern Florida follow.Month Year 1 Year 2 Year 3January 170 180 195February 180 205 210March 205 215 230April 230 245 280May 240 265 290Month Year 1 Year 2 Year 3June 315 330 390July 360 400 420August 290 335 330September 240 260 290October 240 270 295November 230 255 280December 195 220 250a. Construct a time series plot. What type of pattern exists in the data?b. Develop an estimated regression equation that can be used to account for any seasonaland linear trend effects in the data. Use the following dummy variables to account forthe seasonal effects in the data: Jan  1 if January, 0 otherwise; Feb  1 if February,0 otherwise; Mar  1 if March, 0 otherwise; . . . Nov  1 if November, 0 otherwise.Note that using this coding method, when all the 11 dummy variables are 0, the observationcorresponds to an expense in December.c. Compute the monthly forecasts for next year based upon both trend and seasonaleffects.