Table 2.

Problem formulations.

	Mammography problem		Economics problem
	Probability version	Natural frequency version	Probability version	Natural frequency version
Cover story	Imagine you are a reporter for a women’s magazine and you want to write an article about breast cancer. As a part of your research, you focuses on mammography as an indicator of breast cancer. You are especially interested in the question of what it means, when a woman has a positive result (which indicates breast cancer) in such a medical test. A physician explains the situation with the following information:		Imagine you are interested in the question, if career-oriented students are more likely to attend an economics course. Therefore the school psychological service evaluates the correlations of personality characteristics and choice of courses for you. The following information is available:
Version	The probability of breast cancer is 1% for a woman who participates in routine screening. If a woman who participates in routine screening has breast cancer, the probability is 80% that she will have a positive test result. If a woman who participates in routine screening does not have breast cancer, the probability is 9.6% that she will have a positive test result.	100 out of 10,000 women who participate in routine screening have breast cancer. Out of 100 women who participate in routine screening and have breast cancer, 80 will have a positive result. Out of 9,900 women who participate in routine screening and have no breast cancer, 950 will also have a positive result.	The probability that a student attends the economics course is 32.5%. If a student attends the economics course, the probability that he is career oriented is 64%. If a student does not attend the economics course, the probability that he is still career-oriented is 60%.	325 out of 1,000 students attend the economics course. Out of 325 students who attend the economics course, 208 are career-oriented. Out of 675 students who not attend the economics course, 405 are still career-oriented.
Visual aid	• No visualization, or • 2 × 2 table (prob.), or • Tree diagram (prob.)	• No visualization, or • 2 × 2 table (nat. freq.), or • Tree diagram (nat. freq.)	• No visualization, or • 2 × 2 table (prob.), or • Tree diagram (prob.)	• No visualization, or • 2 × 2 table (nat. freq.), or • Tree diagram (nat. freq.)
Question	What is the probability that a woman who participates in routine screening and receives a positive test result has breast cancer?	How many of the women who participate in routine screening and receive a positive test result have breast cancer?	What is the probability that a student attends the economics course if he is career-oriented?	How many of the students who are career-oriented attend the economics course?
	Answer: _______ %	Answer: ____ out of ____	Answer: _______ %	Answer: ____ out of ____