While checking the accuracy of a portable spirometer for ...

[mynx]

While checking the accuracy of a portable spirometer for volumetric measures with a calibrated super syringe, you obtain a mean measured value of 2.7 L. What is the percent error of this in-strument?
 
  a. 1
  b. 10
  c. 30
  d. 90

Question 2

What do we measure to determine the precision of an instrument?
 
  a. Mean measured reference value
  b. Difference between the mean measured and actual reference value
  c. Range of the mean measured reference value
  d. Standard deviation (SD) of the mean measured reference value

[succesfull]

Answer to Question 1

ANS: B

Answer to Question 2

ANS: D
A small SD indicates low variability and high precision.