measures of dispersion

• -          A disadvantage of standard deviation is that it is more difficult to calculate compared to the range and standard deviation becomes less meaningful if your data is not normally distributed as its calculations are based on the mean so it is also distorted by extreme scores
• -          An advantage of Standard deviation is that it takes account of all scores and it is a sensitive measure of dispersion at least more than the range
• -          A disadvantage of the range is that it does not provide any idea of the distribution of values around the centre and does not take individual values into account – only values considered are the 2 most extreme values – which also means the range is seriously affected by extreme scores – the outliers
• -          An advantage of the range is that is that it is quick to calculate and also takes into consideration extreme values
• -          Small standard division means that the data was closely clustered around the mean and the results are consistent – this suggest that all participants scored similarly and responded in similar ways to the IV
• -          Large standard deviation means there was much variation around the mean and there were greater individual differences in that group and the results were less consistent so it means it Is less likely that the IV is affecting all participants in the same way
• -          To calculate standard deviation it involves the calculation of all the scores in the given data set making standard deviation the most powerful of all the measures of dispersion
• -          Standard deviation – is a measure of the variability or spread of a given set of scores from its mean
• -          Range – difference between highest and lowest score then add one which allows for any rounding up or down that has occurred in the data
• -          Measures of central tendency are used to estimate the normal values of a set of data measures of dispersion are used to describe the spread of data or its variation around a central value
• -          Measures of dispersion help us examine the variability within our data sets and help us understand whether the scores given in a set of data are similar to or are very different from each other