Quartile
In descriptive statistics, a quartile is any of the three values that divide the ordered set of data into four equal parts, and thus each part represents 1/4 of the sample or population. Thus, in the case of an ordered sample, ▪ first quartile = lower quartile = is the value at 25% of the ordered sample = 25th percentile ▪ second quartile = median = is the value up to which 50% of the ordered sample is found = 50th percentile, or 5th decile. ▪ third quartile = upper quartile = value from which 25% of the highest values = 75% of the ordered sample = 75th percentile ▪ The difference between the upper and lower quartiles is called the inter-quartile range. Sample 1: Sample: 6, 47, 49, 15, 42, 41, 7, 39, 43, 40, 36 Ordered sample: 6, 7, 15, 36, 39, 40, 41, 42, 43, 47, 49 Q1 / 4 = 15 Q2 / 4 = 40 Q3 / 4 = 43 Example 2: Sample ordered: 7, 15, 36, 39, 40, 41 Q1 / 4 = 15 Q2 / 4 = / 2 = 37.5 Q3 / 4 = 40 ...