A study published in the journal Applied Linguistics (Feb. 2014) investigated the effects of implicit and explicit classroom interventions during the instruction of Japanese to English as- a-first-language (EFL) students. EFL students at a Japanese university were divided into implicit (n = 44) and explicit (n = 37) groups. [Implicit instruction emphasized reading comprehension only, while explicit instruction included both deductive and inductive activities designed to bring learners' attention to rules and patterns.] Following an instruction period, all students were tested on their ability to use epistemic terms such as think, maybe, seem, and may in an essay. A summary of the epistemic type scores for the two groups of EFL students are provided in the table on p. 393.
Table for Exercise 8.50,

a. A 95% confidence interval for (Imp, the true mean epistemic type score of EFL students taught with implicit instruction, is (5.17, 6.63). Based on this interval, is there evidence that (Imp differs from 6?
b. Use the summary information in the table to test the hypothesis that (Imp differs from 6 at a = .05.
c. Explain why the inferences in parts a and b agree.
d. A 95% confidence interval for (Exp, the true mean epistemic type score of EFL students taught with explicit instruction, is (8.67, 10.73). Based on this interval, is there evidence that (Exp differs from 6?
e. Use the summary information in the table to test the hypothesis that (Exp differs from 6 at a = .05.
f. Explain why the inferences in parts d and e agree?

Mean Score Standard Deviation (points) 5.9 9.7 Implicit (n = 44) Explicit (n = 37) 2.4 3.1