Question

identify the independent variable (what you change) and dependent variables (what you measure) in each scenario
scenario

1. a cow is given a growth hormone and then compared to another cow that was not given a growth hormone. both cows were weighed at 2 years.
2. mosquito repellent is sprayed on one arm and the other arm is not sprayed. the number of mosquito bites is counted after 2 hours.
3. one grape is placed in tap water and another grape is placed in salt water. the change in their mass is measured after a day.
4. two different kinds of cars (bmw/mazda) cars are traveling at 60 mph. at a certain point, both cars slam on the brakes. the distance it takes for each car to stop is then measured.
5. pillbugs are placed in a container where they have a choice of a wet or a dry environment. researchers record how much time was spent on each side.

Explanation:

Step1: Recall variable definitions

The independent variable is what is changed in an experiment, and the dependent variable is what is measured as a result of the change in the independent variable.

Step2: Analyze Scenario 1

The thing being changed is whether the cow gets the growth - hormone or not. The thing being measured is the weight of the cow at 2 years. So, independent variable: Administration of growth - hormone; Dependent variable: Cow's weight at 2 years.

Step3: Analyze Scenario 2

The change is spraying mosquito repellent on one arm and not on the other. The measurement is the number of mosquito bites after 2 hours. So, independent variable: Spraying of mosquito repellent; Dependent variable: Number of mosquito bites.

Step4: Analyze Scenario 3

The change is the type of water (tap water or salt water) the grape is placed in. The measurement is the change in grape's mass after a day. So, independent variable: Type of water; Dependent variable: Grape's mass change.

Step5: Analyze Scenario 4

The change is the type of car (BMW or Mazda). The measurement is the braking distance when the cars are traveling at 60 mph and brake. So, independent variable: Car type; Dependent variable: Braking distance.

Step6: Analyze Scenario 5

The change is the type of environment (wet or dry) in the container. The measurement is the time the pillbugs spend on each side. So, independent variable: Type of environment; Dependent variable: Time on each side.

Answer:

1. Independent Variable: Administration of growth - hormone; Dependent Variable: Cow's weight at 2 years
2. Independent Variable: Spraying of mosquito repellent; Dependent Variable: Number of mosquito bites
3. Independent Variable: Type of water; Dependent Variable: Grape's mass change
4. Independent Variable: Car type; Dependent Variable: Braking distance
5. Independent Variable: Type of environment; Dependent Variable: Time on each side