Percentages of public school students in fourth grade in 1996 and in eighth grade in 2000 who were at or above the proficient level in mathematics were given in the ar ticle “Mixed Progress in Math” (USA Today, Au gust 3, 2001) for eight western states:

State 4th grade (1996) 8th grade (2000)

Arizona 15 21 California 11 18 Hawaii 16 16 Montana 22 37 New Mexico 13 13 Oregon 21 32 Utah 23 26 Wyoming 19 25

a. Construct a scatterplot, and comment on any interesting features.

b. Find the equation of the least-squares line that summarizes the relationship between x 5 1996 fourthgrade math proficiency percentage and y 5 2000 eighth-grade math proficiency percentage.

c. Nevada, a western state not included in the data set, had a 1996 fourth-grade math proficiency of 14%.
What would you predict for Nevada’s 2000 eighthgrade math proficiency percentage? How does your prediction compare to the actual eighth-grade value of 20 for Nevada?