1
JEE Main 2013 (Offline)
+4
-1
All the students of a class performed poorly in Mathematics. The teacher decided to give grace marks of 10 to each of the students. Which of the following statistical measures will not change even after the grace marks were given?
A
median
B
mode
C
variance
D
mean
2
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
3
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
4
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
$${13 \over 2}$$
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