1
AIEEE 2012
+4
-1
Let x1, x2,........., xn be n observations, and let $$\overline x$$ be their arithematic mean and $${\sigma ^2}$$ be their variance.

Statement 1 : Variance of 2x1, 2x2,......., 2xn is 4$${\sigma ^2}$$.
Statement 2 : : Arithmetic mean of 2x1, 2x2,......, 2xn is 4$$\overline x$$.
A
Statement 1 is false, statement 2 is true
B
Statement 1 is true, statement 2 is true; statement 2 is a correct explanation for statement 1
C
Statement 1 is true, statement 2 is true; statement 2 is not a correct explanation for statement 1
D
Statement 1 is true, statement 2 is false
2
AIEEE 2011
+4
-1
If the mean deviation about the median of the numbers a, 2a,........., 50a is 50, then |a| equals
A
4
B
5
C
2
D
3
3
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
$${13 \over 2}$$
4
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
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