 So basically measures of central tendency we have three things that is what I was talking about the average how the data is concentrated to into a center if this is the data set this is the central tendency tendency and these two are the dispersion these two are the dispersion and the middle value this is the central tendency that is just a graphical representation so we have measures of central tendency three things one is a mean one is median and the last one is mode okay so mean is the most accurate value if we are not able to take the mean or the data set is in a such a way that we can't take the mean and it is not giving a accurate value we can go for median or mode so mean is very easy it is just average that is mean is denoted by x bar this is called bar so x bar is equal to sigma x by n sorry that is a total score divided by the number of observations so the mean is equal to sigma x by n so we have an example for a very simple example it is we have a data set values are 2, 3, 4, 5 and 6 so the mean would be 2 plus 3 plus 4 plus 5 plus 6 so the total number of observations are 5 that is 1, 2, 3, 4 and 5 so 20 divided by 5 it is 4 so if it is a exam with a score 2, 5 participants are scoring 2, 3, 4 and 5 and 6 so on average every student is scoring marks 4 it doesn't mean that all have scored mark 4 only one person have scored mark 4 one person 2 percent scored above 2 percent scored below but we are saying that on average the score is 4 that is mean value is 4 ok that is the most accurate value of a central tendency usually we take mean in most of the research we take mean and standard deviation if you go search any article you can see mean and standard deviation you can see something like this 2 plus or minus 1.8 or 2.3 plus or minus 2.1 so this is nothing but this is central tendency and this is measure of dispersion this will be mean and this is standard deviation ok so that is measure of central tendency that is the first one mean