Statistical tests

• What can we conclude about correlation?

  Correlation does not cause causation. A correlation does not indicate a casual relationship.
• Scientists have found a correlation between 2 variables. Can you conclude that these variables affected each other? Explain you answer.


  A correlation can not cause a causal relationship/causation. This affect to a variable may be because of a different (named factor).
• What test is used to find a correlation between variables?


  Spearman's rank coefficient correlation
• What test is linked to the word correlation?

  Spearman's rank
• What is the Chi-squared test used for?


  Chi-squared test is used for expected and observed frequencies
• What is the p value compared to the critical value

  The p value is the level of probability of the tested statistical data. Whereas the critical value is the value provided in the table from previous similar investigations.
• What is the calculated value compared to ?

  The calculated value is always compared to the critical value
• What is the degrees of freedom?

  The bigger the sample, the more freedom there will be for data to be statistically significant.
• How is the degrees of freedom calculated for the Chi-squared test?


  Number of categories - 1 Example explanation : This is because if there are 11 people and 11 places, the last person must get the eleventh spot as that is all that is left. So we would have 10 degrees of freedom not 11.
• Why is the students' t-test used?

  To compare means of two sets of data
• What is the spearman's' rank known as in symbols 


  r little s
• What numbers would the spearman's rank always be between?

  the spearmans' rank values are always between -1 and +1