The average marks of 100 students in a class are 48. But while calculating it the marks of a student were written 73 instead of 53. Find out the correct arithmetic mean.
Incorrect ΣX
= N × 
= 100 × 48 = 4800
Correct ΣX = 4800 - 73 + 53 = 4780
4780
Hence Correct 
= 4780/100 = 47.8.
The most suitable average for qualitative measurement is:
Which average is affect most by the presence of extreme items?
The algebraic sun of deviation of a set of n values from A.M. is =:
Comment on whether the following statements are True or False.
Following information pertains to the daily income of 150 families. Calculate the arithmetic means.
|
Income (in Rs.) |
No. of Families |
|
More than 75 More than 85 More than 95 More than 105 More than 115 More than 125 More than 135 More than 145 |
150 140 115 95 70 60 40 25 |
If the arithmetic mean of the data given below is 28, find (a) the missing frequency and (b) the median of the series.
|
Profit per retail shop (in Rs.) |
Number of retail shops |
|
0-10 10-20 20-30 30-40 40-50 50-60 |
12 18 27 – 17 6 |
The following series relates to the daily income of workers employed in a firm. Compute the (a) highest income of lowest 50% workers, (6) minimum income earned by the top 25% and (c) maximum income earned by lowest 25% workers.
|
Daily Income (in Rs.) |
Number of Workers |
|
10-14 15-19 20-24 25-29 30-34 35-39 |
5 10 15 20 10 5 |
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'?
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