The following table shows marks secured by 140 students in an examination- Marks Number of students- 0-10 20- 10-20 24- 20-30 40- 30-40 36- 40-50 20- -Calculate mean marks by the step deviation method-

[ nbsp; Marks amp; Number of students (f_i) amp; Mid value of marks (x_i) amp; u_i = (x_i 25)/10 amp; f ...

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Byju's Answer

Standard XI

Statistics

Mean of Continuous Series

The following...

Question

The following table shows marks secured by 140 students in an examination:
$\begin{matrix} M a r k s & N u m b e r o f s t u d e n t s 0 - 10 & 20 10 - 20 & 24 20 - 30 & 40 30 - 40 & 36 40 - 50 & 20 \end{matrix}$
Calculate mean marks by the step deviation method.

20.4

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25.86

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26.92

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Solution

The correct option is C
25.86

$\begin{matrix} M a r k s & N u m b e r o f s t u d e n t s (f_{i}) & M i d - v a l u e o f m a r k s (x_{i}) & u_{i} = \frac{(x_{i} - 25)}{10} & f_{i} u_{i} 0 - 10 & 20 & 5 & - 2 & - 40 10 - 20 & 24 & 15 & - 1 & - 24 20 - 30 & 40 & 25 (= a) & 0 & 0 30 - 40 & 36 & 35 & 1 & 36 40 - 50 & 20 & 45 & 2 & 40 T o t a l & 140 & 12 \end{matrix} M e a n = a + 10 \times \frac{\sum f_{i} u_{i}}{\sum f_{i}} = 25 + 10 \times \frac{12}{140} = 25.86$

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Similar questions

The following table shows marks secured by 140 students in an examination:
$\begin{matrix} Marks & Number of students 0 - 10 & 20 10 - 20 & 24 20 - 30 & 40 30 - 40 & 36 40 - 50 & 20 \end{matrix}$
Calculate mean marks by the step deviation method.

The following table shows marks secured by 140 students in an examination:
$\begin{matrix} M a r k s & N u m b e r o f s t u d e n t s 0 - 10 & 20 10 - 20 & 24 20 - 30 & 40 30 - 40 & 36 40 - 50 & 20 \end{matrix}$
Calculate mean marks by the step deviation method.

Q. The following table shows the marks scored by

140

students in an examination of a certain paper:

Marks:	0-10	10-20	20-30	30-40	40-50
Number of students:	$20$	$24$	$40$	$36$	$20$

Calculate the average marks by using all the three methods: direct method, assumed mean deviation and shortcut method.

Q. The following table shows the marks scored by 140 students in an examination of a certain paper.

Marks:	0−10	10−20	20−30	30−40	40−50
Number of students:	20	24	40	36	20

Calculate the average marks by using all the three methods: direct method, assumed mean deviation and shortcut method.

Q. The following table shows the marks obtained by 90 students in a certain examination. Calculate the average marks per students by step deviation method.

Marks	10−20	20−30	30−40	40−50	50−60	60−70	70−80	80−90
No. of students	7	13	20	25	10	8	6	1

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The following table shows marks secured by 140 students in an examination: MarksNumber of students0−102010−202420−304030−403640−5020 Calculate mean marks by the step deviation method.

The correct option is C 25.86 MarksNumber of students(fi)Mid−value of marks (xi)ui=(xi−25)10fiui0−10205−2−4010−202415−1−2420−304025(=a)0030−40363513640−502045240Total14012Mean=a+10×∑fiui∑fi =25+10×12140 =25.86

The following table shows marks secured by 140 students in an examination:
$\begin{matrix} M a r k s & N u m b e r o f s t u d e n t s 0 - 10 & 20 10 - 20 & 24 20 - 30 & 40 30 - 40 & 36 40 - 50 & 20 \end{matrix}$
Calculate mean marks by the step deviation method.