Uncertainty Flashcards
what is accuracy what is precision?
Accuracy refers to the closeness of a measured value to a standard or known value.
Precision refers to the closeness of two or more measurements to each other.
What is your definition of uncertainty?
Uncertainty can be defined as the level of unsureness in someone or something.
What are 2 approaches to uncertainty (intrinsic and epistemic)?
Intrinsic » Inherent to the phenomenon
Epistemic » Model inexactness
» Measurement error
» Statistical uncertainty
Name an example for each intrinsic and epistemic uncertainty.
Ex. Intrinsic – deaths (not always known how someone passes away), only know when data being collected, if 5 things were happening (ex. Trauma, cancer, etc.) you don’t know which one
Ex. Epistemic – decrease measurement error, redo experiment, making more measurements, doing measurement in diff conditions
how is uncertainty introduced to LCA?
Because we need to understand that method of LCA is a very heavy assumption based and assumption process. This leads to collected data with uncertainty. Interpretations of data from person to person varies which creates uncertainty as well.
if you are given an emission factor in US what is the uncertainty?
Depends on where you are that determines emission factor of different areas. » Boundary problems
Not all data is released
» Data released may not be accurate
Does it make a difference between where you are in the US?
Yes. Some emission factors like that of Ohio differ from that in California. And even within a state cities may vary and so may cities to state.
What are the emission factors dependent on?
the emission factors are dependent on the electricity generation in that area.
What is captured in these emission factors?
Amount of fossil fuels and electricity generation.
Give 3 examples of fossil fuels.
Coal, natural gas and petroleum
Name 3 renewable sources of electricity.
Solar, wind, hydro
non renewable
Nuclear also reflected on map. Nuclear energy is nonrenewable because the energy nuclear power produces cannot constantly be replenished. An energy source must have resources that can be replenished to be considered renewable.
How do you mitigate uncertainty using significant figures?
Reduce number of significant digits to never more than 2 and in some cases 1
what’s another way to communicate uncertainty?
Data quality assessment (“pedigree”) matrix
