1
AIEEE 2010
+4
-1
For two data sets, each of size 5, the variances are given to be 4 and 5 and the corresponding means are given to be 2 and 4, respectively. The variance of the combined data set is
A
$${5 \over 2}$$
B
$${11 \over 2}$$
C
6
D
$${13 \over 2}$$
2
AIEEE 2009
+4
-1
If the mean deviation of number 1, 1 + d, 1 + 2d,........, 1 + 100d from their mean is 255, then the d is equal to
A
20.0
B
10.1
C
20.2
D
10.0
3
AIEEE 2009
+4
-1
Statement - 1 : The variance of first n even natural numbers is $${{{n^2} - 1} \over 4}$$

Statement - 2 : The sum of first n natural numbers is $${{n\left( {n + 1} \right)} \over 2}$$ and the sum of squares of first n natural numbers is $${{n\left( {n + 1} \right)\left( {2n + 1} \right)} \over 6}$$
A
Statement-1 is true, Statement-2 is true; Statement-2 is a correct explanation for Statement-1
B
Statement-1 is true, Statement-2 is true; Statement-2 is not a correct explanation for Statement-1
C
Statement-1 is true, Statement-2 is false
D
Statement-1 is false, Statement-2 is true
4
AIEEE 2008
+4
-1
The mean of the numbers a, b, 8, 5, 10 is 6 and the variance is 6.80. Then which one of the following gives possible values of a and b?
A
a = 0, b = 7
B
a = 5, b = 2
C
a = 1, b = 6
D
a = 3, b = 4
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