NAGALAND Class 10 Maths Statistics
Arithmetic Mean of Grouped Data
Calculate arithmetic mean of grouped data by using three different methods. Direct, short cut, step deviation methodMode of Grouped Data
The mode of data is the observation that occurs most often. If all the observations are occurring only once, mode is not defined.
The mode may be greater than, less than or even equal to the mean.
Mode is useful in market research.
The mode of data is the observation that occurs most often. If all the observations are occurring only once, mode is not defined.
The mode may be greater than, less than or even equal to the mean.
Mode is useful in market research.Median of Grouped Data
For finding the median we must arrange the given data in increasing or decreasing order.
The frequencies obtained by adding frequency of a class with the sum of frequencies of the preceding classes is called cumulative frequency.Relation Between Central Tendencies
A distribution in which the values of mean, median and mode coincide(i.e. mean = median = mode) is known assymmetrical distribution.
Distribution for which values of mean, median and mode are not equal is known as asymmetrical or skewed distribution.
Empirical formula for moderately asymmetric distributions is given by Median = Mode + 2 mean.Cumulative Frequency Curve
A cumulative frequency distribution is represented graphically by means of a curve called an 'ogive'.
Ogives are of two types- 'less than ogive' and 'more than ogive'
An ogive has the lower/upper limits plotted on the x axis and the cumulative frequency on the y- axis. They are helpful in finding the value of median of the given data.
If a 'less than ogive' and 'more than ogive' for the same data are plotted on the same graph, then the x-coordinate of their point of intersection represents the median for the data.