Understanding Hypotheses in Research

Hypothesis Definitions

• A hypothesis is a tentative prediction about the relationship between two or more variables.
• It is an educated guess about what will happen in an experiment.
• It can be a tentative explanation of a research problem, a possible outcome, or a guess about the research outcome.

Example Hypothesis

• Example: If a plant receives unlimited sunlight, it will grow to its largest possible size.

Hypothesis Characteristics

• Empirical: A hypothesis needs to be testable using the senses. A non-empirical hypothesis is hard to study quantitatively.
• Plausible: Must be based on sound logic and reasonable. Illogical or highly improbable hypotheses shouldn't be tested.
• Specific: A hypothesis must avoid ambiguity; it must clearly define the concepts or variables.
• Testable: Must be possible to investigate whether the relationship is true or false. Data needed to test the hypothesis must be obtainable and analyzed. There needs to be an available way to test the relation.
• Well-formulated hypotheses are crucial to research because illogical or not well defined hypothesis need more work and potentially will lead to wrong conclusion.

Null Hypothesis (H₀)

• Predicts no relationship between dependent and independent variables.
• Assumes a measure of relationship equals zero.
• Represents a theory put forward, believed to be true, or as a basis for argument but not yet definitively proven.
• States the exact opposite of what the investigator expects.

Alternative Hypothesis (H₁)

• Predicts the opposite of the null hypothesis (typically, a relationship does exist).
• States there is a relationship between variables.
• Assumes an observed real effect is present.
• Suggests or advises a potential result or outcome expected by the researcher. It can be directional or non-directional.

Examples of Research Questions and Hypotheses

• Research question 1: Do students work better on Monday mornings than Friday afternoons?
  • Alternative hypothesis (H₁): Students will recall significantly more information on a Monday morning than a Friday afternoon.
  • Null hypothesis (H₀): There will be no significant difference in the amount of information recalled on a Monday morning compared to a Friday afternoon.
• Research question 2: Does eating breakfast affect student performance?
  • Alternative hypothesis (H₁): Students who eat breakfast will perform better on a math exam than students who don't eat breakfast.
  • Null hypothesis (H₀): There will be no significant difference in the performance of students who eat breakfast compared to those who do not.
• Research question 3: Does using a cellphone while driving affect driver performance?
  • Alternative hypothesis (H₁): Motorists who talk on the phone while driving will be more likely to make errors on a driving course than those who do not talk on the phone.
  • Null hypothesis (H₀): There will be no significant difference in the number of errors on a driving course for individuals talking on a phone as compared to individuals who are not talking on a phone.

Hypotheses Regarding Categorical Variables

• Example Research Question: Do the odds of having a stroke increase if you inhale second-hand smoke?
• Variables: Exposure to secondhand smoke (yes/no) and stroke (yes/no ). These are categorical because they fit into pre-defined categories, unlike something measured on a scale.

This quiz focuses on the definitions, characteristics, and examples of hypotheses in research. It explores what makes a good hypothesis and the importance of empirical evidence. Test your knowledge on hypothesis formulation and its role in scientific experimentation.