Probability and Significance

• What is the significance of probability in psychology research?

  It helps manage the risk of errors.
• What are the two competing hypotheses in research?

  Null hypothesis (H0) and alternate hypothesis (H1)
• What does the null hypothesis suggest?

  There is no causal relationship between variables.
• What does the alternate hypothesis suggest?

  There is a causal relationship between variables.
• How is the independent variable manipulated in an experiment?

  By creating separate conditions for testing.
• Why is it important to control for order effects in experiments?

  To reduce bias in participant responses.
• In the example study, what was the independent variable?

  The color of light (green or blue).
• What was the dependent variable in the study example?

  The number of words recalled from a list.
• What was the directional hypothesis in the study example?

  Recall will be better in the green light condition.
• What does a mean score of 13 words in green light indicate?

  Higher recall compared to blue light condition.
• What does a p-value of less than 0.05 indicate?

  Accept the alternate hypothesis with risk.
• What does a probability of 0 represent on a number line?

  Impossible event.
• What does a probability of 1 represent on a number line?

  Certain event.
• What is the probability of flipping a fair coin and getting heads?

  50 percent or 0.5.
• What is the probability of rolling a six on a six-sided die?

  Approximately 17 percent or 0.17.
• Why can we never reach a probability of 0 percent?

  There is always a chance of error.
• What is a type 1 error?

  Accepting a false alternate hypothesis.
• What is a type 2 error?

  Rejecting a true alternate hypothesis.
• How can researchers reduce the likelihood of a type 1 error?

  By using a stronger level of significance.
• How does using a 0.05 level of significance affect type 2 errors?

  It reduces the chance of type 2 errors.
• What is the relationship between type 1 and type 2 errors in hypothesis testing?

  • Type 1 Error: False positive, accepting false hypothesis.
  • Type 2 Error: False negative, rejecting true hypothesis.
  • Adjusting significance levels affects both types of errors.
• How can the courtroom analogy help understand hypothesis testing?

  • Null hypothesis: Innocent until proven guilty.
  • Alternate hypothesis: Guilty based on evidence.
  • Jury's decision reflects acceptance/rejection of hypotheses.
• What are the key steps in hypothesis testing in psychology research?

  1. Formulate null and alternate hypotheses.
  2. Collect data through experimentation.
  3. Analyze data to determine significance.
  4. Accept or reject hypotheses based on probability.
• What is the significance level commonly used by psychologists?

  0.05 or 5 percent.
• Why is probability and significance considered a difficult topic in psychology?

  It involves complex concepts and calculations.
• What is the average occurrence of a type 1 error?

  One in twenty times.
• What is the role of the prosecution in the courtroom analogy?

  To provide strong evidence for guilt.
• How does the jury's decision relate to hypothesis testing?

  It reflects acceptance or rejection of evidence.