Question types

Statistics question types

110 questions across 4 question groups — pick any mix to generate a MATHS paper with step-by-step answer keys.

110
Questions
4
Question groups
5
Question types
Sample Questions

Statistics questions

One sample from each question group in this chapter. Select any group above to see the full set with answer keys.

Let a, b, c, d, e be the observations with mean m and standard deviation s. The standard deviation of the observations a + k, b + k, c + k, d + k, e + k is:
  • s
  • B
    ks
  • C
    s + k
  • D
    $\frac{\text{s}}{\text{k}}$

Answer: A.

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If n = 10, $\overline{\text{X}}=12$ and $\sum\text{x}_\text{i}^2=1530,$ then the coefficient of variation is:
  • A
    36%
  • B
    41%
  • 25%
  • D
    None of these

Answer: C.

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Let $x_1, x_2, ..., x_n $ be n observations. Let $y_i = ax_i + by_i + b$ for $i = 1, 2, 3, ..., n,$ where $a$ and $b$ are constants. If the mean of $x_i's$ is $48$ and their standard deviation is $12,$ the mean of $y_i's \ 55$ and standard deviation of $y_i's$ is $15,$ the values of $a$ and $b$ are:
  • $a = 1.25, b = -5$
  • B
    $a = -1.25, b = 5$
  • C
    $a = 2.5, b = -5$
  • D
    $a = 2.5, b = 5$

Answer: A.

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If the standard deviation of a variable X is $\sigma,$ then the standard deviation of variable $\frac{\text{aX+b}}{\text{c}}$ is:
  • A
    $\text{a}\ \sigma$
  • B
    $\frac{\text{a}}{\text{c}}\sigma$
  • $\Big|\frac{\text{a}}{\text{c}}\Big|\sigma$
  • D
    $\frac{\text{a}\sigma+\text{b}}{\text{c}}$

Answer: C.

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If $x_1, x_2, ..., x_n $ are n values of a variable $X$ and $y_1, y_2, ..., y_n $ are $n$ values of variable $Y$ such that $y_i = ax_i + b, i = 1, 2, ..., n,$ then write $Var(Y)$ in terms of $Var(X).$
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If $X$ and $Y$ are two variates connected by the relation $\text{Y}=\frac{\text{aX+b}}{\text{c}}$ and $\text{Var}(\text{X})=\sigma^2,$ then write the expression for the standard deviation of $Y.$
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If each observation of a raw data whose standard deviation is $\sigma$ is multiplied by a, then write the S.D. of the new set of observations.
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Q 113 Marks Question3 Marks
Two plants A and B of a factory show following results about the number of workers and the wages paid to them:
  Plant A Plant B
No. of workers 5000 6000
Average monthly wages ₹ 2500 ₹ 2500
Variance of distribution of wages 81 100
In which plant A or B is there greater variability in individual wages?
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Q 123 Marks Question3 Marks
The means and standard deviations of heights ans weights of 50 students of a class are as follows:
  Weights Heights
Mean 63.2kg 63.2 inch
Standard deviation 5.6kg 11.5 inch
Which shows more variability, heights or weights?
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Q 153 Marks Question3 Marks
Coefficient of variation of two distributions are 60% and 70% and their standard deviations are 21 and 16 respectively. What are their arithmetic means?
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Calculate mean deviation about median age distribution of $100$ persons given below:
Age
16-20
21-25
26-30
31-35
36-40
41-45
46-50
51-55
No. of persons
5
6
12
14
26
12
16
9
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The number of telephone calls received at an exchange in 245 successive one- minute intervals are shown in the following frequency distribution:
Number of calls
0
1
2
3
4
5
6
7
Frequency
14
21
25
43
51
40
39
12
Compute the mean deviation about median.
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