In a large urban school with over 6,000 students, a random sample of 375 parents were interviewed at the start of a new school year. Of the 375 parents, 280 said that they thought the principal was doing an excellent job. However, when she implemented a stricter grading policy a month into the school year, it was thought that the proportion of parents who thought the principal was doing an excellent job decreased. To investigate, a new random sample of 523 parents was selected, and 358 thought the principal was doing an excellent job.

(a) Do these data support the conclusion that there was a decrease in the proportion of parents who thought the principal was doing an excellent job after the new grading policy was implemented?