c(mg/L)	signál (mV)				average or  all points?		
150.0	22.0	21.0	19.5				
200.0	30.5	31.0	28.0				
250.0	35.0	35.5	30.0				
300.0	40.0	41.0	37.5				
350.0	51.0	49.0	48.0				
400.0	55.0	53.0	54.0				
450.0	64.0	66.5	66.0				
500.0	70.5	71.0	69.0				
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
##### Sheet/List 2 #####
test the intercept!							
c	mAU						
0.12	133.5						
0.23	254.6						
0.36	404.4						
0.51	560.7						
0.62	689.1						
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
							
##### Sheet/List 3 #####
"In the potentiometric determination of Pb2+ in solution, the following calibration data was collected."		
		
	"Pb2+, ppm"	"Emeas, mV"
	15	-338.5
	35	-329.8
	89	-316.5
	150	-312.2
	230	-303.7
	400	-296.4
	500	-295.5
	650	-292.5
		
		
		
"Another solution, whose concentration of Pb2+ was not known, yielded a measured potential of -300.8 mV"		
Report the concentration of lead in the solution in the form of a confidence interval.