The rate of a traveling object varies directly with distance and inversely with time. This relation applies to the Johnsons, as they are traveling by car on their way to a vacation spot 240 miles from their home. They plan to travel at the speed limit of 60 mph. How much time will it take them to travel there, and how much time could they save by going 80 mph?

A. 1 hour; 4 hours
B. 4 hours; 2 hours
C. 3 hours; 1 hour
D. 4 hours; 1 hour

Aresearch study is studying the effects of a new drug for osteoporosis alzheimer's disease (ad) for women above the age of 65 years. a group of individuals with osteoporosis is randomized into two groups. one group is treated conventionally, and the second group is treated with the new medication. assessments are made at 3, 6, 12, 36, and 48 months. the conventionally treated group is assessed for ad using a serum blood test, and the treatment group is assessed for ad using a pet radiotracer that binds to beta-amyloid plaques. in comparing these 2 trial arms, the authors of the study may encounter which type of bias? a. selection bias on the risk of developing b. measurement bias c. confounding bias d. recall bias e. lead-time bias