Research Methods & Writing a Hypothesis

Scientific Method

Hypothesis What you expect to happen

Subjects The who (or what) of the study

Variables The things that can change

Independent Variables (IV) What the experimenter manipulates/changes

Dependent Variables (DV) What changes as a result of the changes in IV

Lab ExperimentsIn a controlled environment

Field ExperimentsNOT in a controlled environmentConducted in a natural setting

Experimental GroupThe critical part of the experiment

is performed on this group Control Group

Does not participate in the critical part of the experiment

Other Methods

Survey Questions on feelings, opinions, behavior

patterns Naturalistic Observation

Watching people without their knowledge You will do this with your observation

assignment

Interview Guided questions

Case StudyCollect details/info about a subject.

Helps determine psych. treatment Psychological Tests

Observe & measure (Objective!) Cross-sectional Method

Study different age groups at same time

Used to understand changes that occur during life span

LongitudinalStudy same person/group over time

Writing Hypotheses

• A hypothesis is used to help guide an experimental investigation. It is an educated guess about the relationship between the independent variable (IV) and dependent variable (DV).

• A hypothesis is testable, and the experimental investigation can be done based on the hypothesis.

Writing Hypotheses

• One way to write a hypothesis is to use an “if…, then…” statement to show cause and effect (relationship).

• In other words, what effect does the independent variable have on the dependent variable? Or what does the independent variable cause the dependent variable to do?

Writing Hypotheses

• If the independent variable changes, then the dependent variable will change.

• You will state the actual variables and describe the type of changes you expect in the hypothesis.

Writing Hypotheses

• Avoid the word “may”

• Avoid predictions

• Avoid conclusions

Writing Hypotheses

• If the independent variable changes, then the dependent variable will change.

OR…

• If the change to the DV is related to IV, then changing the IV will result in a change to DV.

• You will state the actual variables and describe the type of changes you will manipulate and expect to see in the hypothesis.

Example:

Question: Does the amount of sleep affect how well a student will perform on the ISAT?

– What can be changed?

If students increase the amount of sleep they get, then students will get higher scores on their test.

IV: Sleep >>>> change = amount

DV: Test Score >>>> change = increase/higher

Example:

Question: Does the amount of sleep affect how well a student will perform on the ISAT?

– What can be changed?

If student performance on the ISAT is related to the amount of sleep they get, then students that are well rested will get higher scores on their test.

IV: Sleep >>>> change = amount

DV: Test Score >>>> change = increase/higher