The Trial Urban District Assessment (TUDA) is a government-sponsored study of student achievement in large urban school districts. TUDA gives a mathematics test scored from 0 to 500. A score of 262 is a "basic" mathematics level and a score of 299 is "proficient." Scores for a random sample of 1 100 eighth-gr ders in Dallas had 271 with standard error 1.3.

(a) We don't have the 1100 individual scores, but use of the t procedures is surely safe. Why? O
A. Because the sample size is very large.
B. Because the sample doesn't have outliers.
C. Because the data haya strong skew.
D. Because use of the t procedures is always safe.