Coefficient of Variation of Wheat \(={S.D\over Mean}\times 100\)
\(={5.43\over15.5}\times100=29.75\%\)
Coefficient of Variation of Rice\(={S.D\over Mean}\times 100\)
\(={7.16\over19.5}\times100=36.72\%\)
In my opinion, it is more reliable to grow wheat as its c.v. is less i.e. consistency is more.

Mean will increase by 10% as mean is not independent of origin. But S.D. will be same as it is independent of origin.
New Mean = 20 + 10% of 200
= 200 + 20 = 220
S.D. will be same.

New average will be 240 because mean is not independent of origin but it increases or decreases by the same number with which all observations are increased or decreases. But S.D. is independent of origin. Therefore, it will remain same. But c.v. is standard deviation divided by mean. Since S:D. is same but mean has increased, therefore, distribution will become more uniform. It is shown below:
New \(\sum\)X = 10000 + 1000 = 11000
New Mean = 11000/50
= 220
New S.D.
S =\(\sqrt { \frac { { \sum { X } }^{ 2 } }{ n } -\left( \frac { \sum { X } }{ n } \right) ^{ 2 } } \)
Each worker has got a rise of Rs.20,
therefore,
\(\sum\)X² = (220)²x 50
= 48400 x 50
= 24,20,000
S.D. =\(\sqrt { \frac { 24,20,00 }{ 50 } -(220)^{ 2 } } \)
S=\(\sqrt { 48400-48400 } \)
S=0
Since S = 0, therefore c.v. = 0%

Q.D. = 1.5, Coefficient of Q.D. = 0.024

Range = 96, Coefficient of range = 0.92

The high variability in the distribution of income and wealth shows that there are many people who are living at a very low income while there few people who have amassed huge wealth and taking advantage of luxuries of life. In this case, the value of equity is compromised in the society as high level of disparity of income and wealth makes it prone to social unrest.

Techniques that are used to measure the extent of variation or the deviation (also called degree of variation) of each value in the data set from a measure of central tendency, usually the mean or median. Such statistical techniques are called measures of dispersion (or variation).
An average is a single value that represents a set of values in a distribution. It is the central value which represents the entire distribution.
Dispersion on the other hand, measures the extent to which the individual value fall away from the central value.

Q1 =\(\frac{n}{4}\)
observation \(\frac{30}{4}\)observation
Q₁ class is 20-30 Q₁-l₁+\(\frac { \left( N/4-C \right) }{ f } \)(i)
Where l₁=20; f=5; \(\frac{N}{4}\)=7.5; C = 5; i= 10
Q₁ = 20 +\(\frac { \left( 7.5-05 \right) }{ 5 } \)(10)=25
Q₃ =\(\frac{3(n)}{4}\)th observation \(\frac{3(30)}{4}\)=22.5th observation 
Q₃ class is 40-50
Then Quartile of a continuous series can be calculated by the below interpolation formula.
Q₃ =\(\frac { { l }_{ 1 }+\left( 3N/4-C \right) }{ f } \)
Where I₁ = 40-, f= 7; ​​​​​​​\(\frac{3N}{4}\)= 22 .50; C = 18;i = 10
Q₃=40+\(\frac { \left( 22.50-18 \right) }{ 7 } \)(10)=46.42
Quartile Deviation (Q.D) =\(\frac { { Q }_{ 3 }-{ Q }_{ 1 } }{ 2 } =\frac { 46.42-25 }{ 2 } =\frac { 20.42 }{ 2 } \)=10.21
Coefficient of Quartile Deviation = \(\frac { { Q }_{ 3 }-{ Q }_{ 1 } }{ { Q }_{ 3 }+{ Q }_{ 1 } } =\frac { 46.42-25 }{ 46.42+25 } =\frac { 20.42 }{ 71.72 } \)=0.28

First of all we need to convert it into exclusive series.

Method 1:
Here Mid value of the highest class = 42 Mid value of the lowest class = 7
Range = Highest Mid Value-Lowest Mid Value = 42 - 7 = 35
Coefficient of Range =\(\frac{L-S}{L+S}\)
\(\frac{42-7}{42+7}=\frac{35}{49}\)=0.714
Method 2:
Here Upper Limit of highest class = 4.5
Mid value of the lowest class = 44.5
Range Upper Limit of highest class-lower limit of lowest class 44.5 - 4.5 = 40
Coefficient of Range =\(\frac{L-S}{L+S}\)
\(\frac{44.5-4.5}{44.5+4.5}=\frac{40}{49}\)=0.816

First we need to convert cumulative frequency distribution into simple frequency distribution.

Method 1:
Here Mid value of the highest class = 85 Mid value of the lowest class = 15
Range = Highest Mid Value-Lowest Mid Value = 85 -15 = 70
Coefficient of Range =\(\frac{L-S}{L+S}\)
\(\frac{85-15}{85+15}=\frac{70}{100}\)=0.70
Method 2:
Here Upper Limit of highest class = 10
Mid value of the lowest class = 90
Range Upper Limit of highest class-lower limit of lowest class 90 -10 = 80 Kilogram
Coefficient of Range =\(\frac{L-S}{L+S}\)
\(\frac{90-10}{90+10}=\frac{80}{100}\)=0.80