NCERT Solutions for class 11 Maths | Chapter 15 - Statistics

Questions
1 Varience of the following data 2, 4, 5, 6, 8, 17 is
A 13.33
B 23.33
C 33.33
D None of these

Answer:23.33
2 Coefficient of variation of a data is
A Standard deviation/Mean
B (Standard deviation/Mean) * 100
C (Mean/Standard deviation) * 100
D Mean/Standard deviation

Answer:(Standard deviation/Mean) * 100
3 Mode of grouped data is
A (f1 - f0 ) *h /{(2f1 - f0 - f2 )}
B l * (f1 - f0 ) *h /{(2f1 - f0 - f2 )}
C l + (f1 - f0 ) *h /{(2f1 - f0 - f2 )}
D None of these

Answer:l + (f1 - f0 ) *h /{(2f1 - f0 - f2 )}
4 If the mean of a frequency distribution is 8.1 and ∑ƒixi = 132 + 5k, ∑ƒi = 20, then k = 
A 3
B 4
C 5
D 6

Answer:6
5 If mode of a series exceeds its mean by 12, then mode exceeds the median by
A 4
B 8
C 6
D 12

Answer:8
6 If Mean = Median = Mode, then it is
A Symmetric distribution
B Asymmetric distribution
C Both symmetric and asymmetric distribution
D None of these

Answer:Symmetric distribution
7 If the difference of mode and median of a data is 24, then the difference of median and mean is
A 12
B 24
C 8
D 36

Answer:12
8 The median and SD of a distributed are 20 and 4 respectively. If each item is increased by 2, the new median and SD are
A 20, 4
B 22, 6
C 22, 4
D 20, 6

Answer:22, 4
9 Mean of the first n terms of the A.P. a + ( a + d ) + ( a + 2d ) + ………is
A a+nd/2
B a + ( n - 1 )d
C a+(n−1)d/2
D a + nd

Answer:a+(n−1)d/2
10 Let x1 , x2 , x3 , x4 , x5 be the observations with mean m and standard deviation s. The standard deviation of the observations kx1 , kx2 , kx3 , kx4 , kx5 is
A k+s
B s/k
C k*s
D s

Answer:k*s
11 The mean of 1,3,4,5,7, 4 is m . the numbers 3,2,2,4,3,3, p have mean m - 1 and median q . Then, p+q =
A 4
B 5
C 6
D 7

Answer:7
12 If a variable takes discrete values x + 4, x - 7/2, x - 5/2, x - 3, x - 2, x + 1/2, x - 1/2, x + 5 (x > 0), then the median is
A x - 5/4
B x - 1/2
C x - 2
D x + 5/4

Answer:x - 5/4
13 The measure which takes into account all the data items is
A Mean
B Median
C Mode
D None of these

Answer:Mean
14 The mean and variance of 7 observations are 8 and 16, respectively. If five of the observations are 2, 4, 10, 12, 14. then the remaining two observations are
A 4, 6
B 6, 8
C 8, 10
D 10, 12

Answer:6, 8
15 The coefficient of correlation between two variables is independent of
A both origin and the scale
B scale but not origin
C origin but not scale
D neither scale nor origin

Answer:both origin and the scale
16 If the S.D. of the 1,2,3,4,5,………………..10 is σ, then the S.D. of 11,12,13,14,……………..20 is none of these
A 10σ
B σ + 10
C σ
D None of these

Answer:None of these
17 Standard deviation for n observations x1 , x2 , ..........., xn given their mean is x, is
A ∑(xi - x)
B ∑(xi - x)2 /n
C √{∑(xi - x)2 /n}
D √{∑xi2 /n + x2 }

Answer:√{∑(xi - x)2 /n}
18 If Cov(X,Y ) = 0 , then ρ(X,Y) is equal to
A -1
B 0
C 1
D ±1

Answer:0
19 If x and y are independent variables, the Cov(x, y) equals
A 1
B -1
C 0
D None of these

Answer:0
20 If one of the observation is zero then geometric mean is
A (Sum of observation)/n
B (Multiplication of all observations)n
C (Multiplication of all observations)1/n
D 0

Answer:0

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