What are the desiderata (requirements) of a good average? Compare the mean, the median and the mode in the light of these desiderata? Why averages are called measures of central tendency?
"Every average has its own peculiar characteristics. It is difficult to say which average is the " Explain with examples.
What do you understand .by 'Central Tendency'? Under what conditions is the median more suitable than other measures of central tendency?
The average monthly salary paid to all employees in a company was Rs 8,000.
The average monthly salaries paid to male and female employees of the company were Rs 10,600 and Rs 7,500 respectively. Find out the percentages of males and females employed by the company.
1. Calculate the arithmetic mean from the following data:
Class 1019 2029 3039 4049 5059 6069 7079 8089
Frequency 2 4 9 11 12 6 4 2
2. Calculate the mean, median and mode from the following data:
Height in Inches Number of Persons

6263 
2 

6364 
6 


6465 
14 


6566 
16 


6667 
8 


6768 
3 


6869 
1 



Total 
50 

A number of particular articles have been classified according to their weights.
After drying for two weeks, the same articles have again been weighed and similarly classified. It is known that the median weight in the first weighing was 20.83 gm while in the second weighing it was 17.35 gm.
Some frequencies a and b in the first weighing and x and y in the second are missing. It is known that a = 1/3x and b = 1/2 y. Find out the values of the missing frequencies.
Class 
Frequencies 


First Weighing 
Second Weighing 
0 5 
a 
z 
510 
b 
y 
1015 
11 
40 
1520 
52 
50 
2025 
75 
30 
2530 
22 
28 
 Cities A, Band C are equidistant from each other. A motorist travels from A to B at 30 km/h; from B to C at 40 km/h and from C to A at 50 km/h. Determine his average speed for the entire
3. Calculate the harmonic mean from the following data:
ClassInterval 
24 
46 
68 
810 
Frequency 
20 
40 
30 
10 
A vehicle when climbing up a gradient, consumes petrol @ 8 km per
While coming down it runs 12 km per litre. Find its average consumption for to and fro travel between two places situated at the two ends of 25 Ian long gradient.