Mode and Median

•Mode: most frequently seen value (if no numbers repeat then the mode = 0)

•Median: the middle number

–If you have an odd number of data then the median is the value in the middle of the set

–If you have an even number of data then the median is the average between the two middle values in the set. 

Variance (s2)

 

•Mathematically expressing the degree of variation of scores (data) from the mean

•A large variance means that the individual scores (data) of the sample deviate a lot from the mean.

•A small variance indicates the scores (data) deviate little from the mean

Standard Deviation

 

•An important statistic that is also used to measure variation in biased samples.

•S is the symbol for standard deviation

•Calculated by taking the square root of the variance

•So from the previous example of pea plants:

       The square root of 2.5 ; s=1.6

•Which means the measurements vary plus or minus +/- 1.6 cm from the mean