Here's a short story:

In chemistry, the standard state of a material (pure substance, mixture or solution) is a reference point used to calculate its properties under different conditions. In principle, the choice of standard state is arbitrary, although the International Union of Pure and Applied Chemistry (IUPAC) recommends a conventional set of standard states for general use. IUPAC recommends using a standard pressure "p" = 10 Pa. Strictly speaking, temperature is not part of the definition of a standard state. For example, as discussed below, the standard state of a gas is conventionally chosen to be unit pressure (usually in bar) ideal gas, regardless of the temperature. However, most tables of thermodynamic quantities are compiled at specific temperatures, most commonly or, somewhat less commonly, . 

The standard state should not be confused with standard temperature and pressure (STP) for gases, nor with the standard solutions used in analytical chemistry. 

For a given material or substance, the standard state is the reference state for the material's thermodynamic state properties such as enthalpy, entropy, Gibbs free energy, and for many other material standards. The standard enthalpy change of formation for an element in its standard state is zero, and this convention allows a wide range of other thermodynamic quantities to be calculated and tabulated. The standard state of a substance does not have to exist in nature: for example, it is possible to calculate values for steam at 298.15 K and 10 Pa, although steam does not exist (as a gas) under these conditions. The advantage of this practice is that tables of thermodynamic properties prepared in this way are self-consistent. (End of story)

Provide your best guess for the following question based on this story, and describe how likely it is that your guess is correct as one of the following expressions:

Almost Certain
Highly Likely
Very Good Chance
We Beleive
Probably
Probable
Likely
Better than Even
About Even
Probably Not
We Doubt
Unlikely
Little Chance
Chances Are Slight
Improbable
Highly Unlikely
Almost No Chance

Give ONLY the guess and your confidence, no other words or explanation. For example:

Guess: <most likely guess, as short as possible; not a complete sentence, just the guess!>
Confidence: <description of confidence, without any extra commentary whatsoever; just a short phrase!>

Here are a few examples of questions and answers:

Question: What is a standard state?
Guess: a reference point
Confidence: <appropriate level of confidence in this guess>

Question: Used for what?
Guess: to calculate its properties
Confidence: <appropriate level of confidence in this guess>

Question: In what field is this used?
Guess: chemistry
Confidence: <appropriate level of confidence in this guess>

Question: Is its use interchangeable with STP?
Guess: no
Confidence: <appropriate level of confidence in this guess>

Question: Does the standard state of a thing need to actually be possible?
Guess: no
Confidence: <appropriate level of confidence in this guess>

Question: Why not?
Guess: so tables of thermodynamic properties are self-consistent.
Confidence: <appropriate level of confidence in this guess>

Question: What's an example of something that standard state measures?
Guess: unit pressure ideal gas
Confidence: <appropriate level of confidence in this guess>

Now answer the following question in the same format.

Question: What is most data about thermodynamic quantities gathered at?

the standard state