If the mean deviation of number 1, 1 + d, 1 + 2d,.... 1 + 100 d from their mean is 255, then d is equal to.
10
20
10. 1
20. 2
If the standard deviation of a variable x is σ, then the standard deviation of another variable is
σ
None of these
If r is Karl Pearson's coefficient of correlation between two sets of variates, then.
r < 1
r > 1
r < -1
| r | ≤ 1
If the variance of 1,2,3,4, ... 10 is 99/12, then the standard deviation of 3, 6, 9, 12, .... 30 is
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
The values of mean, median and mode coincide, then the distribution is.
Positive skewness
Symmetric distribution
Negative skewness
All of the above
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
1/5
-1/5
2/5
-2/5
For the given data, the calculation corresponding to all values of variates (x,y) is following.The karl Pearson's correlation coefficient is.
0. 2
0.5
0. 66
0. 33
The median of a set of 9 distinct observations is 20.5. If each of the largest 4 observations of the set is increased by 2, then the median of the new set.
is increased by 2
is decreased by 2
is two times the original median
remains the same as that of original set.
