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.