Exercise 2: Observation units and variables
The No Child Left Behind (NCLB) Act of 2001 was a U.S. Act of Congress that supported standardsbased education reform. A widespread criticism of the act was that it did not assert a national
achievement standard – instead each state was allowed to develop their own standard for which
schools faced consequences.
The following maps show a side by side comparison of two relevant variables used by critics of
percent of schools in each state facing consequences and
percent of fourth graders in each state below the basic level in a national reading test.
Keeping your focus only on the presentation in the graphic, answer the following questions.
a. Who or what is the observation unit. Your choices are:
a fourth grader
a state in the U.S.
Clearly pick one of the choices and then write a complete sentence with why
you think it is the right choice.
b. Which of the following best describes the two variables, as depicted in the maps?
both variables are numerical
both variables are categorical with unordered categories
both variables are categorical with ordered categories.
Clearly pick one of the choices and then write a complete sentence with why you
think it is the right choice.
c. Overall, just based on visual examination, does there appear to be a positive or a negative
relationship between the two variables? Explain. (Hint a positive relationship means high
values of one variable tend to track with high values of the other variable; a negative
relationship means high values of one variable tend to track with low values of the other
Positive or negative, and write a couple of sentences to explain your thought process