True value is: 4.2 ppm. Mesured value is: 4.5(+/- 0.3) ppm.

a) what is the absolute error (i.e. bias) in the analysis? the answer that i got for this is 0.30

b) what is the percent relative error in the analysis?

c) what is the absolute uncertainty in the analysis? the answer that i got for this is 0.30(+/- 0.3), let me know if i made a mistake!

d) what is the percent relative uncertainty in this analysis ?