Chem Mini Test

Random error

Occur when there is an equal probability of the reading being too high or too low

• all measurements possess ——- ——

• The last digit in every measurement is always estimated.

Systematic error

Occurs when measurement readings are consistently too high or too low

-caused by the way in which the experiment was conducted

(Ex: read wrong, wrong calibration.. consistent bit wrong)

Accuracy

Refers to how close the reading is to the ‘true’ value

• often indicated using percent error calculation

Precision

Refers how close individual measurements of the same quantity are to each other.

Digital instrument

±0.1

Analog instrument

±0.5

What can be reduced?

Random uncertainties by

• performing multiple trials + mean average

• ____ only!! not eliminated

Absolute uncertainty

(TriangleA) = ± .001 g

Percentage uncertainty

triangleA / A x 100

Addition and subtraction

The uncertainty in the result of ____ or ____ two measurements is the sum of their absolute uncertainties.

multiplication division

The uncertainty in the result of ____ or _____ two measurements is the sum of the percentage uncertainties.

Which experimental error can be eliminated by modifying an experiments method/ procedure?

Systematic error