In 1998, the number of newly reported cases of tuberculosis (TB) was about 21,210 and decreased by about 4.73% each year from 1998 to 2002. Write an exponential decay model giving the number of newly reported cases of TB y (in thousands),t years after 1998. All I know how to do is A = 21,210 D:

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)