Q2 of 35 Page 375

From the prices of shares X and Y below, find out which is more stable in value:

Here


For X


Mean where n is number of terms




=


=


=


Standard deviation = √variance= √35=5.91


Coefficient of variation


For Y


where n is number of terms


=



=


=


=


Standard variance = √variance= √4=2


Coefficient of variation


Covariance of x covariance of Y


⇒ X is more variable and Y is more stable than X


More from this chapter

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10

The diameters of circles (in mm) drawn in a design are given below:


Calculate the standard deviation and mean diameter of the circles.


[Hint: First make the data continuous by making the classes as 32.5-36.5, 36.5-40.5,


40.5-44.5, 44.5 - 48.5, 48.5 - 52.5 and then proceed.]

 1

From the data given below state which group is more variable, A or B?

 3

An analysis of monthly wages paid to workers in two firms A and B, belonging to the same industry, gives the following results:


(i) Which firm A or B pays larger amount as monthly wages?


(ii) Which firm, A or B, shows greater variability in individual wages?

 4

The following is the record of goals scored by team A in a football session:


For the team B, mean number of goals scored per match was 2 with a standard deviation 1.25 goal. Find which team may be considered more consistent?