A survey was conducted using a sample of history professors selected at random from the California State Universities. The professors...

1. TRANSLATE the sampling information

• Given information:
  • Random sample of history professors
  • Selected from California State Universities
  • Asked about textbook publishers

• What this tells us: The source population is history professors at California State Universities

2. INFER the generalization rule

• Key principle: Random sampling allows generalization only to the population from which the sample was selected
• Cannot extend results beyond the source population
• Why? Other populations may have different characteristics (different textbook preferences, publishers, etc.)

3. INFER the correct scope

• Source population: History professors at California State Universities
• Valid generalization: All history professors at all California State Universities
• This matches Choice C exactly

Answer: C. All history professors at all California State Universities

Why Students Usually Falter on This Problem

Most Common Error Path:

Weak INFER reasoning about generalization scope: Students often think "bigger sample = broader generalization" and choose overly broad populations like all history professors nationwide (Choice B) or all professors in the US (Choice A).

They miss that geographic and institutional boundaries matter - professors at different university systems or in different states may use different textbooks and publishers. Random sampling only ensures the sample represents the specific population it came from.

This may lead them to select Choice B (All history professors in the United States).

Second Most Common Error:

Poor TRANSLATE of population boundaries: Students may focus on the "professors" part while missing the "history" restriction, leading them to think the results apply to all professors at California State Universities.

They fail to recognize that the sample was specifically limited to history professors, so results cannot be extended to professors in other disciplines who likely have different textbook needs.

This may lead them to select Choice D (All professors at all California State Universities).

The Bottom Line:

This problem tests understanding that statistical generalization has strict boundaries - you can only generalize to the exact population you sampled from, no matter how logical broader generalizations might seem.