Q7 of 23 Page 62

The enrolment in a school during six consecutive years was as follows:

1555, 1670, 1750, 2013, 2540,2820


Find the mean enrolment of the school for this period.

Here,


We have to find the mean of the given enrolments of the school


Now,


At first,


We’ll find the sum of all the observations


Thus,


Sum of all the observations = 1555 + 1670 + 1750 + 2013 + 2540 + 2820


= 12348


Now,


Total number of observations = 6


Hence,


Mean enrolments =


=


= 2058


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5

Following table shows the points of each player scored in four games:

















Player



Game



Game



Game


3



Game


4



A


B


C



14


0


8



16


8


11



10


6


Did not


Play



10


4


13


 6

The marks (out of 100) obtained by a group of students in a science test are 85, 76, 90, 85, 39, 48, 56, 95, 81 and 75.

Find the:


(i) Highest and the lowest marks obtained by the students.


(ii) Range of the marks obtained.


(iii) Mean marks obtained by the group.

 8

The rainfall (in mm) in a city on 7 days of a certain week was recorded as follows:























Day



Mon



Tue



Wed



Thurs



Fri



Sat



Sun



Rainfall


(in mm)



0.0



12.2



2.1



0.0



20.5



5.5



1.0



(i) Find the range of the rainfall in the above data.


(ii) Find the mean rainfall for the week.


(iii) On how many days was the rainfall less than the mean rainfall?

 9

The heights of 10 girls were measured in cm and he results are as follows:

135, 150, 139, 128, 151, 132, 146, 149, 143, 141.


(i) What is the height of the tallest girl?


(ii) What is the height of the shortest girl?


(iii) What is the range of the data?


(iv) What is the mean height of the girls?


(v) How many girls have heights more than the mean height?