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Measures of Central Tendency
From the following distribution, calculate the missing frequency if N = 100 and Median = 30.
|
Marks |
No. of Students |
|
0-10 10-20 20-30 30-40 40-50 50-60 |
10 ? 25 30 ? 10 |
In the question, two frequencies are missing f1 and f2. We will get one frequency from summation of frequencies and the other from median formula :
|
Marks |
f |
c.f. |
|
0-10 10-20 20-30 30-40 40-50 50-60 |
10 f1 25 30 f2 10 |
10 10 + f1 35 + f1 65 + f1 65 + f1 + f2 75 +f1 + f2 |
|
Σ f = 100 |
We two that the sum of frequencies is equal to the cumulative frequency of the last class interval. Hence
75 + f1 + f2 = 100
or f1 + f2 = 100-75 = 25 .... (i)
We have been given median (30) which must be in 30 - 40 class interval.
Hence class interval = 30-40
Median = 30 (given)
Substituting the value of f, in (i) equation we get,
15 + f2 = 25
Hence f2 = 25 - 15 = 10
Sponsor Area
The following table gives production yield in kg. per hectare of wheat of 150 arms in a village. Calculate the mean, median and mode production yield.
|
Production yield (kg. per hectare) |
50-53 |
53-56 |
56-59 |
59-62 |
62-65 |
65-68 |
68-71 |
71-74 |
74-77 |
|
Number of farms |
3 |
8 |
14 |
30 |
36 |
28 |
16 |
10 |
5 |
The size of land holdings of 380 families in a village is given below. Find the median size of land holdings.
|
Size of Land Holdings (in acres) |
Number of families |
|
less than 100 100-200 200-300 300-400 400 and above |
40 89 148 64 39 |
What do you mean by 'Average'?
Pocket expenditures of 6 students are (Rs.) 6,12,18,24,30 and 36 respectively. Find out arithmetic mean.
Name various kinds of statistical averages?
Give formula of weighted averages.
Give formula of calculating arithmetic average of a continuous series.
What is arithmetic mean?
Define median.
Define mode.
Sponsor Area
Sponsor Area