Inferential stats

• Inferential stats

  See if the results are affected by chance rather than the effect of the IV on the DV.

  Probability= working out the likelihood of something happening

  Calculating the size of the difference between data. If the difference is too small, we assume that differences in results are probably down to chance factors.
• Hypothesis'

  Null: predicts that there will be no difference between the scores, if there is a difference then it is down to chance

  Alternative: predicts there will be a difference

  Once you calculate the probability of chance factors affecting the results, you will accept or reject the null.

  Null = insignificant

  Alternative = significant
• Probability

  P < 0.05 = 1/20 that it is down to chance

  The academic convention of the cut-off point for deciding whether to accept or reject the null hypothesis is equal to or less than 0.05

  
  

  P > 0.05 = more than 5% probability results are down to chance and are insignificant
• Mann Whitney U Test

  Ua = na nb + (na (na + 1)/2) - Σ Ra

  Ub = na nb + (nb (nb + 1)/2) - Σ Rb

  
  

  U = test and result

  N = number of participants

  R = rank

  a = group a

  b = group b

  Σ = total
• Spearmans Rank correlation coefficient

  Rs = 1 - 6(Σ d^2)/n (n^2 - 1)