- Mean , Median , Mode
- Quartile , Inter quartile
The three measures of central tendency for ungrouped data are :
The mean (or average) of a number of observations is the sum of the values of all the observations divided by the total number of observations.
So, `bar x =
(sum_(i=1)^n x_i)/ n`.
For an ungrouped frequency distribution, it is `bar x = (sum_(i=1)^n f_ix_i)/(sum_(i=1)^n f_i)`
The median is that value of the given number of observations, which divides it into exactly two parts.
If n is an odd number, the median = value of the `((n + 1)/2)^(th)` observation.
If n is an even number, median = Mean of the values of the `(n/2)^(th)` and `(n/2 + 1)^(th)` observation.
The mode is that value of the observation which occurs most frequently, i.e., an observation with the maximum frequency is called the mode.
Shaalaa.com | Measures of Central Tendency
Yield of soyabean per acre in quintal in Mukund's field for 7 years was 10, 7, 5, 3, 9, 6, 9. Find the mean of yield per acre.
The marks (out of 100) obtained by 7 students in Mathematics' examination are given below. Find the mode for these marks.
99, 100, 95, 100, 100, 60, 90
60, 70, 90, 95, 50, 65, 70, 80, 85, 95.
Find the mean, median and mode of the data.
The calculated mean of 50 observations was 80. It was later discovered that observation 19 was recorded by mistake as 91. What was the correct mean?