STT 231 EXAM 2 COMPREHENSIVE ASSESSMENT PAPER 2026 COMPLETE QUESTIONS AND ANSWERS GRADED A

STT 231 EXAM 2 COMPREHENSIVE
ASSESSMENT PAPER 2026 COMPLETE
QUESTIONS AND ANSWERS GRADED A+

●● Variable.
Answer: Any characteristic (or value) recorded for each case


●● Categorical variable.
Answer: Identify a case as a measure of a group, placing each case into
exactly one of two or more groups, called levels.
Example: Year (first year, second year, third year...)


●● Nominal variable.
Answer: Groups with no logical arrangement
Example: (eye color, major, gender)


●● Ordinal Variable.
Answer: Groups with logical arrangement
Example: (first year, second year, third year)


●● Numerical variable.
Answer: Measure a numerical quantity for each use.

, Example: Credits (0,1,2,3)


●● Discrete variable.
Answer: Limited values in a variables domain. No in between numbers
Example: (Number of students in a class, number of siblings...)


●● Continuous variable.
Answer: Any value in a variables domain.
Example: (98.64, 12.347 seconds)


●● Why are average and proportion not variables when considering
yourself to be the observational unit..
Answer: They don't describe the characteristic of a single student.
Instead, they summarize the combined characteristics of all students
simultaneously. These are actually statistics.


If you changed the observational unit to be "classes at MSU" then they
would be variables.


●● Explanatory Variable.
Answer: A variable manipulated by the researcher


●● Response Variable.