researcher is studying the conditions under which commercially raised shrimp reach maximum weight gain. Two water temperatures (25 degrees, 35 degrees) and four water salinity levels (10%, 20%, 30%, 40%) are selected for study. Shrimp are raised in containers with specified water temperatures and salinity levels. The weight gain of the shrimp in each container is recorded after a six week study period

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)