If the standard deviation of a variable x is σ, then the standard deviation of another variable is
σ
None of these
In a class of 100 students there are 70 boys whose average marks in a subject are 75. If the average marks of the complete class is 72, then what is the average marks of the girls?
73
65
68
74
If r is Karl Pearson's coefficient of correlation between two sets of variates, then.
r < 1
r > 1
r < -1
| r | ≤ 1
The mean deviation from the mean of the set of observations -1, 0, 4 is
3
1
-2
2
Consider the following statementsi. Mode can be computed from histogramii. Median is not independent of change of scaleiii. Variance is independent of change of origin and scaleWhich of these is/ are correct?
only (1)
only (ii)
only (i) and (ii)
only (i), (ii) and (iii)
If the standard deviation of the observations -5, -4, 03, -2, -1, 0, 1, 2, 3, 4, 5 is √10. The standard deviation of observations 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 will be.
√10 + 20
√10 + 10
√10
If the variance of 1,2,3,4, ... 10 is 99/12, then the standard deviation of 3, 6, 9, 12, .... 30 is
The Standard deviation of n observations x1,x2,---xn is 2. If xi2 = 100, then n is
10 or 20
5 or 10
5 or 20
5 or 15
The values of mean, median and mode coincide, then the distribution is.
Positive skewness
Symmetric distribution
Negative skewness
All of the above
If in a frequency distribution, the mean and median are 21 and 22 respectively, then its mode is approximately.
24
25 . 5
20. 5
22. 0
