CBSE Class 10-Mathematics: Chapter –14 Statistics Part 1

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Question 1:

Marks obtained by students are given below

Marks obtained by 70 students

Marks

No. of Students

Answer:

Marks obtained by 70 students

Marks

No. of students

The corresponding value of marks for

Question 2:

The sum of deviations of a set of values , measured from is and the sum of deviations of the values from is . Find the value of and the mean

Answer:

We have

Subtracting (2) from (1), we get

we get

Mean

Hence and mean

Question 3:

Prove that

Answer:

To prove algebraic sum of deviation from mean is zero

We have,

Now

Hence,

Question 4:

Compute the median from the following data

Compute the median from the following data

Mid Value

Frequency

Answer:

Here, we are given the mid values. So, we should first find the upper and lower limits of the various classes. The difference between two consecutive values is

Lower limit of a class Midvalue

Upper limit

Calculate of Median

Calculate of Median

Mid-value

Class Groups

Frequency

Cumulative Frequency

We have

The cumulative frequency first greater than N i.e. is and the corresponding class is is the median class

Now,

Median

Median