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Author Question: In using the chi-square test for independence, one should be aware that the expected frequencies ... (Read 85 times) |
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
Multiple experimental evidences have confirmed that at the molecular level, cancer is caused by lesions in cellular DNA.
Aspirin is the most widely used drug in the world. It has even been recognized as such by the Guinness Book of World Records.
It is believed that the Incas used anesthesia. Evidence supports the theory that shamans chewed cocoa leaves and drilled holes into the heads of patients (letting evil spirits escape), spitting into the wounds they made. The mixture of cocaine, saliva, and resin numbed the site enough to allow hours of drilling.
Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.