Ms. james has a 6-square foot bulletin board and a 12-square bulletin board. she wants to cover both boards with index cards without gaps or overlaps. each index card has an area of 1/4 square foot. how many index cards does she need?

Anew test for ra is being developed. the test is administered to 750 patients with ra and 750 without ra. for the sake of the question, assume the prevalence of ra in this population is 50%. of the 750 patients with ra, 575 have a positive result. of the 750 patients without ra, 150 have a positive result. what is the positive predictive value of the new test? a575/(575+150) b. 600/(600+ 150) c. 575/(575+125) d. 600/(600+ 125)