Question

A sample of 120 fifth-graders and another sample of 100 third-graders each took an identical writing exam. All the students’ exams were judged according to whether the performance met the state scholastic Level 3 standard. Among the fifth graders, 81 of the 120 met the standard. Among the third graders, 55 of the 100 met the standard. Construct and interpret a 90% confidence interval for the difference in the population proportion of fifth graders meeting the standard and the population proportion of third graders meeting the standard. Also, using a hypothesis test at alpha=0.05, assess whether the true proportion of fifth graders meeting the standard is greater than the true proportion of third graders meeting the standard (give the test statistic and P-value of your test) State which statistical method you used.

Answer 1