For a us census clock based on the 2000 census, the birth light would flash every 10 seconds, the death light every 16 seconds, the immigration light every 81 seconds, and the emigration light every 900 seconds, to indicate gains and losses in population.

a. if the birth and death lights flashed at the same time, how many seconds would pass before they flashed together again?

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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