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JEE Main Math Class 12 Statistics Part 1 Questions
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© examsnet.com
Question : 63
Total: 115
If the data
x
1
,
x
2
,
.
.
.
.
.
.
.
,
x
10
is such that the mean of first four of these is 11 , the mean of the remaining six is 16 and the sum of squares of all of these is 2,000 ; then the standard deviation of this data is :
[April 12, 2019 (I)]
2
√
2
2
4
√
2
Validate
Solution:
According to the question,
x
1
+
x
2
+
x
3
+
x
4
4
=
11
⇒
x
1
+
x
2
+
x
3
+
x
4
=
44
x
5
+
x
6
+
.
.
.
.
+
x
10
6
=
16
⇒
x
5
+
x
6
+
.
.
.
.
.
+
x
10
=
96
and
x
1
2
+
x
2
2
+
.
.
.
.
.
x
10
2
=
2000
∵
standard deviation,
σ
2
=
∵
x
i
2
N
−
(
x
)
2
=
2000
10
−
(
44
+
96
10
)
2
=
4
⇒
σ
=
2
© examsnet.com
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