For each description below, identify if the best study would be an experiment or an observational study.

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A company offers typing lessons and the owner wants to evaluate whether or not people type faster after finishing their program.

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A pharmaceutical company researcher needs to determine how much their new drug increases blood hemoglobin.

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A nurse at a dialysis clinic wants to determine what percent of their patients come from an impoverished upbringing.

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A steel manufacturing plant is developing a new smelting process. A quality control engineer wants to determine if the new process impacts the tensile strength of the steel that they produce.

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The senior analyst at a marketing firm is investigating demographic information for a local metropolitan area. She needs to know how much households spend on groceries per month.