Equations

• What is step 1 of Spearmans's rank?

  Rank each set of data. 1 for highest value. If a tie, add ranks together and divide by 2. Then skip to next rank.
• What is step 2 of Spearman's rank?

  Calculate the difference in rank and put into column E.
• What is step 3 of Spearman's rank?

  Square the difference (removes negative values).
• What is step 4 of Spearman's rank?

  Work out total of column F giving the sum (∑) of the differences squared (d²). Then ×6.
• What is step 5 of Spearman's rank?

  Complete Spearman's rank correlation fomula, where n is the number of pairs of data.
• What is step 6 of Spearman's rank?

  Work out statistical significance. Reject null hypothesis, or likely occured by chance? 95% significance level tests if 5 in 100 chance results are by chance and correlation doesn't exist in all countries populations.
• What is step 7 of Spearman's rank?

  What does the result mean? Can null hypothesis be rejected?
• What is step 1 of Mann Whitney test?

  Label data sets 1 & 2. If different values, smaller 1 and larger 2.
• What is step 2 of Mann Whitney test?

  Rank all scores highest to lowest in the whole data set in both columns. If rank is same the add ranks and divide by 2.
• What is step 3 of Mann Whitney test?

  Total the ranks at the bottom of columns A & B.
• What is step 4 of the Mann Whitney test?

  Calculate U values for both samples where n = number of samples in the column. U¹ + U² should equal n¹ × n², if not there is a mistake.
• What is step 5 of Mann Whitney test?

  Work out statistical significance and see if we can reject null hypothesis. Take lower of U values and compare to critical value. Use sample size to find value.
• What does the value for U suggest in the critical value?

  If U value is less than critical value, null hypothesis can be rejected with 95% confidence and alternate hypothesis can be accepted.
• What do the top and bottom lines of a box & whiskers show?

  The highest and lowest values in the data set.
• What is the top and bottom quartiles in a box & whiskers?

  The median of the top and bottom halves of the data set.
• What is the median?

  The middle value of a data set
• What is the interquartile range on a box & whiskers?

  The value of the top quartile to the bottom quartile (box)