Understanding Statistics 1#12 Quartiles of Data
Download as PPTX, PDF0 likes202 views
The document explains the concept of quartiles in statistics, describing their role in dividing a dataset into four parts for analysis. It provides methods for calculating the first (Q1), second (Q2/median), and third (Q3) quartiles using both odd and even data sets, including specific examples. The process of finding quartiles involves determining the median and considering the lower and upper halves of the data set.
Related topics:1 of 3
Downloaded 11 times
Understanding Statistics 1#12 Quartiles of Data
- 2. Quartiles of Data Measures of relative positions or QUARTILES - Quartiles are used to draw Box and Whisker Plots - Quartile divide a data set up as follow Data lower half upper half Q1 Q2(median) Q3 Note: there are only three quartiles not four as it divide the dataset in four parts.
- 3. Quartiles of Data Q1 => the number ≥ 25% of the data Q2 => the number ≥ 50% of the data Q3 => the number ≥ 75% of the data Finding quartile is just an exercise of finding median - Q2 is the median of data set - Q1 median from start up to Q2 - Q3 median from Q2 up to the end Find Quartile for following odd number of Data set: 8,9,2,10,3,5,7,12,15 First order the data: 2,3,5,7,8,9,10,12,15 - 8 is the median = Q2 - Q1: we look at lower half from 2 to 8 INCLUDED - Q1 = 5 - Similar Q3 = 10 (8 is also include in calculating Q3!) Find Quartile for following even number Data set: 10,12,14,15,14,16,17,18,10,19,17,17 -Order Dataset: 10,10,12,14,14,15,16,17,17,17,18,19 -Middle values are 15&16; we average them => Q2 = 15.5 -For lower half we have from 10 to 15 as we have an even number. We split data in two. Q1 will be average between 12&14 Q1 = 13 -For upper half the interval is between 16-19 -Q3 is average between 17 & 17 Q3 = 17