SHEET # 4: Validity

• Develop a 2 by 2 table the include the following information:
• Column represents the biopsy and rows represents physical examination
  • Physical exam: positive (1600 cases; 1000 normal)
  • 2400 biopsy proven cases
  • 6000 normal

		BIOPSY
		POSITIVE	NEGATIVE	TOTAL
POSITIVE		1600	1000
NEGATIVE
		2400	6000

• We are conducting a study to determine the validity of the physical exam to diagnose breast cancer using the biopsy as gold standard. The results are as follows:

• Physical exam: positive (1600 breast cancer cases; 1000 normal control )
• 2400 biopsy proven breast cancer cases
• 6000 normal