8.49 Confidence intervals and English-language tests for international students: The International English Language Testing System (IELTS) has six modules, one of which assesses listening skills. IELTS researchers reported that a recent mean for everyone who completed this module in 1 year was 6.00 and the standard deviation was 1.30 (2013). A sample of 63 international students who were accepted to study at the University of Melbourne in Australia had mean IELTS listening scores of 7.087 with a standard deviation of 0.754 (O’Loughlin & Arkoudis, 2009).

a. Calculate the 95% confidence interval for this sample.

b. State in your own words what we learn from this confidence interval.

c. What information does the confidence interval give us that we also get from a hypothesis test?

d. What additional information does the confidence interval give us that we do not get from a hypothesis test?