data distributions

• a histogram displays the frequency of continuous numerical data. The frequency is placed on the Y-axis and the continuous variable(weight, height, age group) is based on the X-axis.
• A normal distribution is an arrangement of data that is symmetrical and forms a bell-shaped pattern where the mean, median and/or mode falls in the centre at the highest peak. More participants are at the middle and less at either side.
• the mode in a normal distribution curve is the highest/midpoint. the highest point in a histogram is the most frequent score
• the median in a normal distribution curve is the highest/midpoint. an equal number of scores are on either side
• the mean in a normal distribution curve is the highest/midpoint. there should be an equal number of outlier scores on either side.
• standard deviations in normal distributions

  when data is normally distributed, 68% of scores in the data set fall within one standard deviation, and 95% of scores are within two standard deviations of the mean.
• statistical infrequency in NDC

  how far someone's score is from the mean score is a way of determining abnormalities
• skewed distribution

  the distribution of scores is asymmetric. Most of the scores are on one side, with long skews on the opposite side to the majority of scores
• positive skew

  more scores at the lower end of the graph, outliers at the higher end
• negative skew

  more scores at the higher end of the graph, outliers at the lower end
• mode in skewed distributions

  the mode is the most frequent, so it is the highest point
• median in skewed distributions

  at the point where 50% of the graph is either side(between mode and mean)
• mean in skewed distributions

  shifted towards the outlier scores in the long tail(skew)