Question

A scientist testing the effects of a chemical on lettuce yield, sprays a field with the chemical. A second field does not receive the chemical. The amount of lettuce harvested from each field is measured. Bottom of Form

What is the hypothesis?

What is the independent variable?

What is the dependent variable?

What is the control group?

What is the experimental group?

What are the possible standardized variables? (Hint: This is not expressly mentioned in the description so you will have to think about the experimental design.)

Answer 1

Ans. #1. Hypothesis: The treatment with chemical increases lettuce yield.

#2. Independent variables: The variable that acts as the factor/ inputs, etc. that present the cause of variation in outputs.

Here, the “chemical” being sprayed acts as independent variable because it (may) affects the output (lettuce yield) of the experiment.

#3. Dependent variable: A ‘variation’ that depends on the independent variable for the its change is called dependent variable.

# Since the lettuce yield depends (or, assumed to depend) on the independent variable (chemical), it’s the dependent variable.

#4. Control group: The group that receives no treatment during experiment is called the control group.

Here, the second field that does not receive chemical treatment acts as control group.

#5. Experimental group: The group that receives specified treatment (here, chemical treatment) during the experiment is called the experimental group.

Here, the first field that does receive chemical treatment acts as experimental group.

#6. A variable that is kept constant or standardized throughout the experiment is called a standardized variable.

Here, the yield of control group may acts as the standardized variable.

# The yield of control group remains almost constant throughout the experiment.