Study 2 You conduct a study to examine the effect of a new medication to prevent arthritis in older adults. You enroll 206 participants 65-80 years of age who do not have arthritis and assign half to receive the with the new drug (E+) and half to receive placebo (E-). You follow the study participants over 2 years to measure how many develop arthritis (D+) and how many remain free of arthritis (D-). During follow-up 8% of the participants were lost to follow-up (LTF). Use the dataset "arthritis206" to conduct analyses to answer questions 7-17 below. Variable Description Code participant Unique study identification (ID) number for each study participant Numeric variable follow_time months followed in study (until onset of arthritis, end of study, or LTF) (max time = 24 months, 2 years) Numeric variable new_drug Treatment (exposure): New drug 0=placebo (unexposed), 1=new drug (exposed) arthritis Arthritis diagnosed during follow-up 0=no arthritis 1=arthritis 7. What type of study is this (i.e. what is the study design)? [5 points] 8. Describe two benefits of the study design used. [6 points] 9. What is the null hypothesis that you are testing in this trial? [5 points]