Chapter R, Problem 5.50RE

Cramming Students in two basic Spanish classes were required to learn 50 new vocabulary words. One group of 45 students received the list on Monday and studied the words all week. Statistics summarizing this group’s scores on Friday’s quiz are given. The other group of 25 students did not get the vocabulary list until Thursday. They also took the quiz on Friday, after “cramming” Thursday night.

Then, when they returned to class the following Monday, they were retested—without advance warning. Both sets of test scores for these students are shown.

1. a) Did the week-long study group have a mean score significantly higher than that of the overnight crammers?
2. b) Was there a significant difference in the percentages of students who passed the quiz on Friday?
3. c) Is there any evidence that when students cram for a test, their “learning” does not last for 3 days?
4. d) Use a 95% confidence interval to estimate the mean number of words that might be forgotten by crammers.
5. e) Is there any evidence that how much students forget depends on how much they “learned” to begin with?