Identify the situations that involve inference about a difference between two population means. a. The National Assessment of Educational Progress (NAEP) is the largest national assessment of what students in the U. S. know and can do in various subject areas. Is the mean score for 8th graders in Texas on the NAEP math test higher than the national average of 281?
b. The mean score on the NAEP math test for 8th graders in Texas is compared to the mean score for 8th graders in California.
c. A school district uses questions from the NAEP math test to assess the effectiveness of a new computer-based math instruction. Students take the test before and after the intervention and the district looks for improvement.
d. A school district compares a computerized math program to individualized tutoring for 4th graders who have difficulty in math. They use questions from the NAEP math test in a pre-test and post-test design to assess improvement in math skills for the two groups.