Sponsor Area
Which measure of dispersion is the best and how?
Standard deviation is the best measures of dispersion, because it posseses most of the characterstics of an ideal measure of dispersion.
Sponsor Area
Some measures of dispersion depend upon the spread of values whereas some calculate the variation of values from a central value. Do you agree?
Yes we agree with the statement Range and quartile deviation measure the dispersion by calculating the spread within which the values lie i.e. they depend on the spread of values. On the other hand, mean deviation and standard deviation calculate the variation of value from a central value.
In a town 25% of the persons earned more than Rs. 45000, whereas 75% earned more than Rs. 18000. Calculate the absolute and relative values of dispersion.
Absolute value of dispersion i.e. 
A batsman is to be selected for a cricket team. The choice is between X and Y on the basis of their five previous scores which are:
|
X |
Y |
|
25 |
50 |
|
85 |
70 |
|
40 |
65 |
|
80 |
45 |
|
120 |
80 |
Which batsman should be selected if we want
(i) a higher run getter, or
(ii) a more reliable batsman in the team?
Batsman -A
|
Scores (X) |
|
|
|
25 |
–45 |
2025 |
|
85 |
+15 |
225 |
|
40 |
–30 |
900 |
|
80 |
+10 |
100 |
|
120 |
+50 |
2500 |
|
ΣX= 350 |
Σx2= 50 |
Batsman B
|
X |
(X) |
n2 |
|
50 |
-12 |
144 |
|
70 |
+8 |
64 |
|
65 |
+3 |
9 |
|
45 |
-17 |
289 |
|
80 |
+18 |
324 |
|
ΣX=310 |
ΣX2= 830 |
Sponsor Area
Mock Test Series
(X)
(X2)