In a laboratory, smokers are asked to drive using a computerized driving simulator and cover the maximum distance possible, while avoiding rear-end collisions. some volunteers are given a real cigarette to smoke immediately before the test. others smoke a fake cigarette without nicotine. the number of collisions the two groups make is to be compared. in this study, the dependent variable is:

The number of collisions.

An object, a time period, an event, an idea or any other category a person is intended to measure is known as a variable. There are two types of variables: the independent and the dependent. An independent variable is a variable that doesn't depend on other factors and doesn't change by other variables you're trying to measure. On the other hand, a dependent variable is related to another factors and changes accordingly. In this case, the dependent variable is the number of collisions.  

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