Statistics CBSE Questions & Answers

Statistics

This is Mathematics Class 09 Statistics CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
One of the sides of a frequency polygon is
  • A
    neither of the coordinate axes
  • B
    either of the coordinate axes
  • C
    the y-axis
  • D
    the x-axis
    Correct
2
Which of the following is not a measure of central tendency ?
  • A
    Median
  • B
    Mean
  • C
    Standard deviation
    Correct
  • D
    Mode
3
The mean for counting numbers through 100 is
  • A
    49.5
  • B
    51
  • C
    50.5
    Correct
  • D
    50.5
4
the mean of first n natural numbers is
  • A
    \({{n - 1} \over 2}\)
  • B
    \({{n + 1} \over 2}\)
    Correct
  • C
    \({{n\left( {n + 1} \right)} \over 2}\)
  • D
    \({{n\left( {n - 1} \right)} \over 2}\)
5
The mean of first four prime numbers is
  • A
    4.25
    Correct
  • B
    4
  • C
    4.5
  • D
    3.75
6
If, for the set of observations 4, 7, x, 8, 9, 10 the mean is 8, then x is equal to
  • A
    9
  • B
    8
  • C
    12
  • D
    10
    Correct
7
The smallest of three consecutive even integers is 32. Then, the mean of the three integers is
  • A
    35
  • B
    33
  • C
    34
    Correct
  • D
    36
8
If \(\bar x\) represents the mean of observations \({x_1},{x_2},...,{x_n},\) then value of \(\sum\limits_{i = 1}^n {({x_i} - \bar x)} \)is
  • A
    n – 1
  • B
    - 1
  • C
    1
  • D
    0
    Correct
9
If each observation of the data is increased by 3, then their mean
  • A
    is decreased by 3
  • B
    is increased by 3
    Correct
  • C
    becomes 3 times the original mean
  • D
    remains the same
10
The mean of 30 observations is 12 . If 25 is subtracted from the sum of observations, then remaining sum is
  • A
    365
  • B
    385
  • C
    335
    Correct
  • D
    375
11
The mean of prime numbers between 30 and 40 is
  • A
    36
  • B
    34
    Correct
  • C
    31
  • D
    37
12
If \({\bar x_1},{\bar x_2},{\bar x_3},...,{\bar x_n}\) are the means of n groups with \({n_1},{n_2},...{n_i}\) number of observations respectively, then the mean \(\bar x\) of all the groups taken together is
  • A
    \({{\sum\limits_{i = 1}^n {{n_i}{{\bar x}_i}} } \over {2n}}\)
  • B
    \({{\sum\limits_{i = 1}^n {{n_i}{{\bar x}_i}} } \over {\sum\limits_{i = 1}^n {{n_i}} }}\)
    Correct
  • C
    \({{\sum\limits_{i = 1}^n {{n_i}{{\bar x}_i}} } \over {{n^2}}}\)
  • D
    \(\sum\limits_{i = 1}^n {{n_i}{{\bar x}_i}} \)
13
Sheila received x marks in two of her tests and y marks in three other tests. Her average score in all the five tests in terms of x and y is
  • A
    \({{2x + 3y} \over 5}\)
    Correct
  • B
    \({{2x + 3y} \over 2}\)
  • C
    \({{3x + 2y} \over 3}\)
  • D
    \({{3x + 2y} \over 5}\)
14
The median for the the digits 1, 2, 3, …, 9 is
  • A
    5.5
  • B
    4
  • C
    5
    Correct
  • D
    4.5
15
The marks obtained by 10 students in a mathematics test are 75, 90, 70, 50, 70, 50, 75, 90, 70 and 75. Their median mark is
  • A
    72.5
    Correct
  • B
    75
  • C
    71.5
  • D
    70