Cumulative Frequency Diagram Median. If we divide a cumulative frequency curve into quarters the value at the lower quarter is referred to as the lower quartile the value at the middle gives the median and the value at the upper quarter is the upper quartile. For example there are 7 numbers in the example above so replace n by 7 and the median is the 7 1 2 th value 4th value.
8 14 15 16 17 18 19 50. It looks like an upside down s. If you have n numbers in a group the median is the n 1 2 th value.
The mean of these numbers is 19 625.
L is the lower class boundary of the group containing the median. How to plot a less than type ogive. Find the upper and lower quartiles. It looks like an upside down s.
