Refer to the Bilingual Research Journal (Summer 2006) study of the relationship of Spanish (first-language) grammatical knowledge to English (second-language) reading, presented in Exercise. Recall that three simple linear regressions were used to model the English reading (ESLR) score (y) as a function of Spanish grammar (SG), Spanish reading (SR), and English grammar (EG), respectively.
a. If the researchers want to predict the ELSR score (y) of a native Spanish-speaking adult who scored 50% in Spanish grammar (x), how should they proceed?
b. If the researchers want to estimate the mean ELSR score E (y) of all native Spanish-speaking adults who scored 70% in Spanish grammar (x), how should they proceed?