statistic

statistic

1. summary values that describe a sample

   • organise & summarize data
   • conclusion

2. descriptive

   • organize, summarize, simplify results
   • frequency distribution
     • allow viewing of entire set of scores
     • tables
     • graphs
       • histogram
       • polygon
       • bar graph
   • contral tendency
     • identify the most typical & representative value of the grp
     • mean
     • mode
     • median
   • variability
     • spread of score in a distribution
     • standard deviation
       • average distance from the mean
     • variance
       • average squared distance from the mean
   • distribution
     • normal
       • bell-shlaped
       • symmetrical
       • Kurtosis
         • how flat or peaked the distribution is
         • Leptokurtic
           • tall
           • thin
         • Platykurtic
           • short
           • more dispersed
       • mean = median = mode
     • positively skewed
     • negatively skewed
   • standard score / z-score
     • how many sd unit a raw score falls from the mean of distribution
   • probability
     • expected relative frequency of a particular outcome

3. inferential

   • use the result to make generailizations about the population
   • sampling distribution of mean
     • all possible sample means that occur when samples of a particular size are drawn from a population
   • standard error of mean
     • sd of sampling distribution of mean
   • critical value
     • inner edge of the region of rejection
     • depends on criterion
     • z-score isnt beyond critical -> sample represent the underlying raw score population = relationship exist -> reject H0 & retain Ha
   • hypothesis
     • experimental
       • predicted outcome that may / may not find in the study
       • one-tailed test
         • X predict the direction in which scores will change
       • two-tailed test
     • statistical
       • alternative hypothesis
         • predicted relationship exists
           • change in variable -> change in predicted outcome
       • null hypothesis
         • predicted hypothesis do not exist
           • sampling error
           • poorly represented data