# NCERT Class 11-Math՚S: Exemplar Chapter – 15 Statistics Part 12 (For CBSE, ICSE, IAS, NET, NRA 2022)

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**Question 27**:

Following are the marks obtained by 9 students in a mathematics test:

The mean deviation from the median is:

(A)

(B)

(C)

(D)

**Answer: (C)**

**Question 28**:

The standard deviation of the data is

(A)

(B)

(C)

(D)

**Answer: (A)**

**Question 29**:

Let be n observations and be their arithmetic mean. The formula for the standard deviation is given by

(A)

(B)

(C)

(D)

**Answer: (C)**

**Question 30**:

The mean of observations is and their standard deviation is . The sum of all squares of all the observations is

(A)

(B)

(C)

(D)

**Answer: (C)**

**Question 31**:

Let be the observations with mean m and standard deviation s. The standard deviation of the observations is

(A)

(B)

(C)

(D)

**Answer: (A)**

**Question 32**:

Let be the observations with mean m and standard deviation s. The standard deviation of the observations is

(A)

(B)

(C)

(D)

**Answer: (C)**

**Question 33**:

Let be observations. Let for , where and are constants. If the mean of is and their standard deviation is , the mean of is and standard deviation of is , the values of and should be

(A)

(B)

(C)

(D)

**Answer: (A)**

**Question 34**:

Standard deviations for first natural numbers is

(A)

(B)

(C)

(D)

**Answer: (D)**

**Question 35**:

Consider the numbers . If is added to each number, the variance of the numbers so obtained is

(A)

(B)

(C)

(D)

**Answer: (D)**