The following table shows marks secured by 140 students in an examination- begin array - c - c - Wline Marks - Number of students- Wline 0-10 - 20 Wline10-20 - 2411Wline20-30 - 40 Wline 30-40 - 36 1Wline40-50 - 20 Wline-end array Calculate mean marks by the step deviation method-A- 25B- 25-86C- 26-92D- 20-4

The correct option is B 25.86[ Marks amp; Number of students (f_i) amp; Mid value of marks (x_i) amp; u_i = (x_i 25) ...

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Standard VII

Mathematics

Arithmetic Mean and Range

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

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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.

The marks obtained by 40 class X students in a math paper of 50 marks, are presented in the table. Find the mean using direct method.
$\begin{matrix} Marks obtained & Number of students 0 - 10 & 3 10 - 20 & 4 20 - 30 & 13 30 - 40 & 15 40 - 50 & 5 \end{matrix}$

Q. The marks obtained by 40 students in a class are presented in the form of a table. Find the mean marks using direct method.

\begin{matrix} Marks obtained & Number of students 0 - 10 & 3 10 - 20 & 4 20 - 30 & 13 30 - 40 & 15 40 - 50 & 5 \end{matrix}

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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 25.86MarksNumber of students(fi)Mid−value of marks (xi)ui=(xi−25)10fiui0−10205−2−4010−202410−1−2420−304025(=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.