What primarily limits generalization of a statistical valuation result?
Correct Answer
C) The population and conditions supported by data, assumptions and validation
The population, property characteristics, period and conditions actually supported by the data and model constrain application. Membership in the original population alone does not guarantee validity if selection is biased. Extension to a new population or future period requires additional justification and validation, rather than being automatically authorized or categorically impossible.
Why This Is the Correct Answer
Option C is correct because a statistical valuation result can be applied credibly only to the population and conditions that the data, model assumptions and validation actually support. A sample statistic is an estimate for the sample and only one indicator for the broader population. Extending a result to a new population or later period needs additional justification and validation.
Why the Other Options Are Wrong
Option A: A shared state boundary between the comparable sales and the subject
Option A, a shared state boundary between the comparables and the subject, is not what limits generalization. A political boundary does not determine whether the data represent the subject's market; similarity of market, characteristics and conditions does.
Option B: Having properties of equal or newer age than the subject alone
Option B, having properties of equal or newer age than the subject, is an arbitrary condition and not the governing limit. Age is one characteristic among many, and its use depends on the market and the data rather than a fixed rule.
Option D: A rule restricting each statistical result to later sales in the same tax district
Option D describes a rule restricting each result to later sales in the same tax district, which is not a recognized principle. Tax district lines do not define the scope of a statistical result; the supported population and conditions do.
Results travel only as far as data
A statistical result applies where the data, assumptions and validation reach. Going beyond that requires new support.
How to use: Use this when an answer choice offers a boundary or age rule in place of data support.
Exam Tip
Prefer answers tied to data, assumptions and validation over answers based on administrative boundaries or fixed rules.
Common Mistakes to Avoid
- -Assuming results apply anywhere within the same state or tax district
- -Treating an age cutoff as the factor that controls generalization
- -Assuming membership in the original population makes results valid even with biased selection
Concept Deep Dive
Analysis
This question tests the limits on applying a statistical result beyond the data that produced it. The reasoning is that a result is supported only for the population, property characteristics, time period and conditions represented in the data, model assumptions and validation, not by arbitrary administrative boundaries or age rules.
Background Knowledge
Any statistic computed from a sample is a point estimate that describes that sample and serves as one indicator for the population it represents. Generalizing to properties, periods or markets outside what the data cover requires evidence that conditions are comparable. Biased selection can undermine a result even within the original population.
Real-World Application
An appraiser builds a regression from suburban single-family sales and is asked to apply it to a rural property with acreage. Because the model's data do not include similar rural properties, the appraiser seeks additional evidence before relying on it.
More Statistics Questions
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An appraiser estimates a market-wide price trend using only sales data from one brokerage that specializes in luxury homes, without checking how other segments are represented. What is the principal concern?
Compared with analyzing one matched sale pair for one feature, what can a suitably specified multiple regression do?
The base-period median sale price is $400,000 and the current-period median is $460,000. Compute the price relative defined as current ÷ base, as a decimal to three places.
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Assessment-to-sale ratios are 0.94, 0.96, 0.98, 1, 1.01. Compute the arithmetic mean. Report as a decimal ratio to three places.
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Previous Question
Sale prices are $255,000, $280,000, $300,000, $320,000, $355,000. Using the median of each half including the overall median (Tukey hinges), Q1=$280,000 and Q3=$320,000. Compute the interquartile range Q3−Q1, to the nearest dollar.
Next Question
Sale prices have an interquartile range of $80,000. Using the normalized interquartile range (0.7413 × IQ), what is the approximate standard deviation for normally distributed data?