Use the Following Information for Questions

Multiple Choice

Use the following information for questions:
An experiment is conducted with 15 seniors who are taking Spanish at Oak View High School. A randomly selected group of eight students is first tested with a written test and a day later with an oral exam. To avoid order effects, the other seven students are tested in reverse order. The instructor is interested in the difference in grades between the two testing methods. SPSS is used to obtain descriptive statistics for the grades of the two tests.
-What is the value of the standard error for the difference in mean grades between the two testing methods?

A) 0.395
B) 0.529
C) 0.563
D) 0.660