The number of X-rays taken and X-ray costs over the last year at the Royal Island Hospital are given below:

Month	# of X-rays	Cost $
January	6,250	28,000
February	7,000	29,000
March	5,000	23,000
April	4,250	20,000
May	4,500	22,000
June	3,000	17,000
July	3,750	18,000
August	5,500	24,000
September	5,750	26,000
October	2,950	17,300
November	4,000	19,800
December	7,050	28,300

Required:

1. Using the least-of-squares regression method, predict the total X-ray costs for the upcoming month if the Royal Island Hospital expects to take 6,900 X-rays.

2. Using the high-low method, predict the total X-ray costs for the upcoming month if the Royal Island Hospital expects to take 6,900 X-rays.

3. How can you explain the different cost estimates that you obtained using the two different methods above?