Please choose observational study or experiment for each. Thanks!

For each of the following. state whether it is an observational study or an experiment: a) From December 2007 through March 2012. researchers at the University of Pittsburgh studied a new medication to treat osteoporosis in frail elderly women. The researchers administered a daily dose of the medication or a placebo by injection along with calcium and vitamin D supplements. Then the researchers measured the hip and spine bone density of each patient at 12 and 24 months. Results were published in the Journal of the American Medical Association (JAMA) in April 2015. [ Select ] . V' b) Educational psychologists investigate the impact of different types of instruction on learning. in one study, researchers taught a math lesson to 9thgraders using the "Inventing to Prepare for Learning (IPL)" instructional cycle. A second group of students received traditional "tell and practice" instruction. After the lessons. both groups studied a worked example of a math problem on their own. Then they took a test that included problems like the worked example. The journal Cognition I and instruction published the results in 2004. ' [59'9\"] V c) In June 2011 The Washington Post published the results of a poll about the war in Afghanistan. in the poll 1,502 US. adults answered the question, \"Do you think the U5. made the right decision or _____.__._-u_ may] d) Over a 17-year period researchers studied a sample of 707 individuals from a single community. They recorded the number of hours each individual spent watching television during adolescence and early aduithood. In later years, they recorded the number of aggressive acts by individuals in the study. Science magazine published the results in 2002 in an article titled "Television Viewing and the wrong decision in using military force in Afghanistan?" [53'3\"] Aggressive Behavior during Adolescence and Adulthood.\" [59'3\"] VF e) The Nurses' Health Study periodically gathers information from 238,000 registered female nurses. In one of their studies called "Red meat consumption during adolescence among premenopausal women and risk of cancer,\" researchers surveyed a total of 39,268 premenopausal nurses. Each nurse completed a questionnaire about her diet during high school. During the 7 years of the study, 455 nurses developed invasive premenopausal breast cancer. Researchers found a strong association between red meat consumption and risk of breast cancer. i [59'3\"] Vi