A study is conducted to determine the effectiveness of a weight-loss gym routine. A simple random sample of 10 people were selected and their weight before and after 6 weeks of this program were measured. [Calculate after before.] Test at a 5% significance level. Person Before After 1 250 230 2 285 245 3 300 265 7. What is the null hypothesis? a: D = 0 b. D<0 4 166 150 5 243 250 c. d> 0 6 190 185 - 7 204 200 8 260 210 9 285 240 10 240 200