Reference no: EM132432533

Problem: This exercise is taken from the textbook exercises in your syllabus, exercise 7.45. Z tests are often used when a researcher wants to compare his or her sample to known population norms. The Graded Naming Test (GNT) asks respondents to name objects in a set of 30 black-and-white drawings. The test, often used to detect brain damage, starts with easy words like kangaroo and gets progressively more difficult , ending with words like sextant. The GNT population norm for adults in England is 20.4. Roberts (2003) wondered whether a sample of Canadian (hooray for Canada!) adults had different scores from adults in England. If they were different, the English norms would not be valid for use in Canada (hooray for Canada!). The mean for 30 Canadian adults was 17.5. For the purposes of this exercise, assume the standard deviation of the adults in England was 9.2.

Required:

Question 1: Calculate the 95% confidence interval for these data.

Question 2: Calculate the effect size, Cohen's d, for these data and interpret the result in complete sentences (e.g., "Small effect size." Is not acceptable; "The small effect size means that X is lower than Y but not sufficiently lower that it would require action," is better)