|Class 10 Maths Statistics||Median of Grouped Data|
Median of Grouped Data
Median is a measure of central tendency which gives the value of the middle-most observation in the data. In case of ungrouped data, we first arrange the data values of the observations in ascending order. Then, if n is odd, the median is the (n+1)/2 th observation. But in case of Grouped data, it is difficult to find (n+1)/2 th observation. We use formula to find Median.
We first find cumulative frequency & then locate the class whose cumulative frequency is greater than (and nearest to) n/2 , where n is total observations. This is called the median class
where l = lower limit of median class,
Numerical: The following frequency distribution gives the monthly consumption of electricity of 68 consumers of a locality. Find the median.
Step 1: Find Cumulative Frequency
Step 2: Find Median Class
Step 3: Apply formula to find Median
Applying the formula, Median = 125 + (34 -22)/20 * 20 = 137