The OECD conducts the Program for International Student Assessment and in 2012 tested 510,000 15-year-old high school students in 65 countries to assess their performance in math, reading, and science. The results are in the data file for the countries whose average score was 500 or more in science. Assume that the number of students who took the test is greater than 3000 in each country.

a) Which countries’ science scores are above the OECD average of 501 but not significantly above at the 0.5% level?

b) What is the 95% confidence interval for Canada’s score of 525?

c) Is Japan’s score significantly less than 550 at the 0.05 level?