The Sign Test

• inferential statistics


  a way of determining whether differences or relationships between variables are statistically significant or have occurred by chance
• statistical significance


  the researcher can state that the relationship between the variables is due to more than just chance- they can accept the alternative hypothesis and reject the null hypothesis
• probability


  the likelihood that certain events will occur
• 3 pieces of information needed to locate the critical value


  -the significance level desired

  -the number of ppts. in the investigation

  - whether the hypothesis is directional or non- directional
• accepted level of probability in psychology

  p_<0.05 or 5%
• value for the calculated value to be to be significant


  it has to be equal to or lower than the critical value
• difference between a one-tailed and two-tailed test


  one-tailed test=directional hypothesis

  two-tailed test=non directional hypothesis
• sign test


  a statistical test used to analyse the difference in scores between related items
• 3 criteria for a sign-test


  -looking at a difference between variables, not association

  -use repeated measures or matched pairs design

  - data is nominal