distribution

what is normal distribution

a symmetric bell shaped distribution curve

mean = median = mode

SD and normal distribution

68% scores - 1SD from mean

95% scores - 2SD from mean

99.7% scores - 3SD from mean

what are the 2 types of skewed distribution

positive skew

negative skew

» occurs when distribution scores are asymmetric - majority of scores are on one side

where does mode, median and mean lie on a skewed graph

mode = highest point as it is the most frequent score

median = between mode and mean

mean = shifted towards the long tail

positive skew

most scores are at lower end of graph

mode > median > mean

negative skew

most scores are at higher end of graph

mean > median > mode