Question 1 Find the mean marks of students for the following distribution beginarray 1 - 1 Whinew - mathbf Marks - mathbf Number of students Whline0 - and - above - 80 Whline60 - and - above - - 28 Whline90 - and - above - - 88 Whline100 - and - above - 0 Whlineendarray

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Standard X

Mathematics

Assumed Mean Method of Finding Mean

Question 1 Fi...

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Question 1
Find the mean marks of students for the following distribution
$\begin{matrix} M a r k s & N u m b e r o f s t u d e n t s 0 a n d a b o v e & 80 10 a n d a b o v e & 77 20 a n d a b o v e & 72 30 a n d a b o v e & 65 40 a n d a b o v e & 55 50 a n d a b o v e & 43 60 a n d a b o v e & 28 70 a n d a b o v e & 16 80 a n d a b o v e & 10 90 a n d a b o v e & 8 100 a n d a b o v e & 0 \end{matrix}$

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Solution

$\begin{matrix} M a r k s & C l a s s m a r k s & N u m b e r o f s t u d e n t s & f_{i} & f_{i} x_{i} 0 - 10 & 5 & 80 & 3 & 15 10 - 20 & 15 & 77 & 5 & 75 20 - 30 & 25 & 72 & 7 & 175 30 - 40 & 35 & 65 & 10 & 350 40 - 50 & 45 & 55 & 12 & 540 50 - 60 & 55 & 43 & 15 & 825 60 - 70 & 65 & 28 & 12 & 780 70 - 80 & 75 & 16 & 6 & 450 80 - 90 & 85 & 10 & 2 & 170 90 - 100 & 95 & 8 & 8 & 760 100 - 100 & 105 & 0 & 0 & 0 \sum f_{i} x_{i} = 4140 \end{matrix}$
$∴ M e a n = \frac{\sum f_{i} x_{i}}{N} = \frac{4140}{80} = 51.75$

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Q. Question 1
Find the mean marks of students for the following distribution

\begin{matrix} M a r k s & N u m b e r o f s t u d e n t s 0 a n d a b o v e & 80 10 a n d a b o v e & 77 20 a n d a b o v e & 72 30 a n d a b o v e & 65 40 a n d a b o v e & 55 50 a n d a b o v e & 43 60 a n d a b o v e & 28 70 a n d a b o v e & 16 80 a n d a b o v e & 10 90 a n d a b o v e & 8 100 a n d a b o v e & 0 \end{matrix}

Q. In a college 50% students are boys out of which 40% have got 80% and above marks. Overall, 45% of all the students have got 80% and above marks. Find the percentage of girls who have got less than 80% marks.

250 students of class X of a school appeared in a test of 100 marks and the data about the marks secured is a below

$\begin{matrix} M a r k s s e c u r e d & N u m b e r o f s t u d e n t s 0 - 20 & 20 20 - 40 & 35 40 - 60 & 65 60 - 80 & 60 80 - 100 & 70 \end{matrix}$

Find the modal vlaue of the above data. [2 MARKS]

Q. Find the mean from the following data:

Marks	No. of Students
Above 0	80
Above 10	77
Above 20	72
Above 30	65
Above 40	55
Above 50	43
Above 60	28
Above 70	16
Above 80	10
Above 90	8
Above 100	0

Q. Following is the distribution of marks of 70 students in a periodical test:

Marks	Number of students
Marks less than 10 Marks less than 20 Marks less than 30 Marks less than 40 Marks less than 50	3 11 28 48 70

Draw a cumulative frequency curve for the above data and find the median.

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Question 1 Find the mean marks of students for the following distribution MarksNumber of students0 and above 8010 and above 7720 and above 7230 and above 6540 and above 5550 and above 4360 and above 2870 and above 1680 and above 1090 and above 8100 and above 0

MarksClass marksNumber of studentsfifixi0−10 5 8031510−20 15 7757520−30 25 72717530−40 35 651035040−50 45 551254050−60 55 431582560−70 65 281278070−80 75 16645080−90 85 10217090−100 95 88760100−100 105 000 ∑fixi=4140 ∴ Mean=∑fixiN=414080=51.75