The sales manager of various sporting goods stores has been running a national advertising campaign for a few months. The monthly advertising costs (in thousands of dollars) for a 10-month period and the corresponding net income (in thousands of dollars) (before taxes) are presented in the table opposite.

Months	Net income before taxes (y) ($000)	Monthly advertising cost (x) ($000)
January	135.0	11.0
February	212.0	18.0
March	180.0	12.2
April	212.0	19.8
May	200.0	17.5
June	162.0	15.2
July	150.0	14.2
August	172.0	16.5
September	155.0	13.0
October	180.0	15.0

The scatter plot of the pairs of observations is presented below.