A researcher would like to evaluate the claim that large doses of vitamin C can help prevent the common cold. One group of participants is given a large dose of the vitamin (500 mg per day), and a second group is given a placebo (sugar pill). The researcher records the number of colds each individual experiences during the 3-month winter season. Identify the dependent variable for this study. Is the dependent variable discrete or continuous? What scale of measurement (nominal, ordinal, interval, or ratio) is used to measure the dependent variable?