Statistical tests

• What is the purpose of a statistical test?

  A: To determine whether the results of an experiment are significant or due to chance.
• What does the null hypothesis (H₀) state?

  A: There is no significant difference or relationship between the variables being tested.
• What does a p-value represent?

  A: The probability that the observed results occurred by chance, assuming the null hypothesis is true.
• What is the usual significance level in biology experiments?

  A: 0.05 (5%)
• When would you use a chi-squared test?

  A: To test the significance of the difference between observed and expected frequencies in categorical data.
• What is a critical value in a statistical test?

  A: A threshold value that the test statistic must exceed for the results to be significant.
• What does the Spearman's rank correlation coefficient measure?

  A: The strength and direction of a correlation between two variables.
• When would you use the Student's t-test?

  A: To compare the means of two groups to see if the difference is significant.
• What type of data is required for the chi-squared test?

  A: Categorical data in the form of frequencies.
• What does it mean if the p-value is less than 0.05?

  A: The null hypothesis is rejected, and there is a significant difference.
• What does it mean if the p-value is above 0.05?

  A: The null hypothesis is accepted, and the results are not significantly different.
• What is the purpose of a control group in an experiment?

  A: To provide a baseline for comparison and ensure that the results are due to the independent variable.