Thane Company is interested in establishing the relationship between electricity costs and machine hours. Data have been collected and a regression analysis prepared using Excel. The monthly data and the regression output follow:

Month	Machine Hours	Electricity Costs
January	2,500	$	18,400
February	2,900	$	21,000
March	1,900	$	13,500
April	3,100	$	23,000
May	3,800	$	28,250
June	3,300	$	22,000
July	4,100	$	24,750
August	3,500	$	22,750
September	2,000	$	15,500
October	3,700	$	26,000
November	4,700	$	31,000
December	4,200	$	27,750

Summary Output
Regression Statistics
Multiple R	.965
R Square	.932
Adjusted R2	.925
Standard Error	1,425.18
Observations	12.00

	Coefficients	Standard Error	t Stat	P-value	Lower 95%	Upper 95%
Intercept	3,726.88	1,682.82	2.21	0.05	(22.69)	7,476.45
Machine Hours	5.77	0.49	11.7	0.00	4.67	6.87

If the controller uses the high-low method to estimate costs, the variable cost per machine hour is:

$6.25.

$6.90.

$5.77.

$11.70.