Experimental Design (1.1.2) Review

Conducting an experiment most logically follows

• making a prediction.

• designing an experiment.

• identifying a question.

• analyzing the data.

The independent variable is

• a process used to carefully plan experiments in order to investigate scientific questions or problems

• the variable being measured and whose value is influenced by another variable

• a series of steps repeated over and over until the desired outcome is obtained

• variable that the researcher intentionally changes to determine its influence on the dependent variable.

Read the following:

A researcher wanted to test the effect of caffeine on sleep. Fifty students volunteered to participate in the study and signed up for one of two nights. Thirty-three students participated on Tuesday night. They each were given two cups of regular coffee to drink one hour before going to sleep. Seventeen students participated on Wednesday night. They each were given two cups of decaffeinated coffee to drink one hour before going to sleep. Each student was monitored with an EEG (a test that looks at brain function) to record exactly when they fell asleep. Students in the caffeine group took significantly longer to fall asleep. The researcher concluded that caffeine interferes with the ability to fall asleep.

What is the dependent variable in this experiment?

• EEG results

• amount of caffeine

• number of students

• night on which they slept

Repeating a series of steps over and over until the desired outcome is obtained is termed

• collaborative.

• independent.

• iterative.

• experimental.

Which of the following would most likely be the independent variable in the following hypothesis?

Hypothesis: If plants are given white light, then they will grow better.

• plants

• white light

• growth

• nothing...it is not mentioned in the hypothesis.