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JEE Main Math Class 12 Statistics Part 1 Questions
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© examsnet.com
Question : 5
Total: 115
The mean and variance of 7 observations are 8 and 16 respectively. If one observation 14 is omitted a and
b
are respectively mean and variance of remaining 6 observation, then
a
+
3
b
−
5
is equal to _______.
[30-Jan-2023 Shift 1]
Your Answer:
Validate
Solution:
x
1
+
x
2
+
.
.
.
.
.
+
x
7
7
=
8
x
1
+
x
2
+
x
3
.
.
.
+
x
6
+
14
7
=
8
⇒
x
1
+
x
2
+
.
.
.
.
+
x
6
=
42
∴
x
1
+
x
2
.
.
.
.
+
x
6
6
=
42
6
=
7
=
a
∑
x
i
2
7
−
8
2
=
16
Σ
xi
2
=
560
⇒
x
1
2
+
x
2
2
+
.
.
.
+
x
6
2
=
364
b
=
x
1
2
+
x
2
2
+
.
.
.
+
x
6
2
6
−
7
2
=
364
6
−
49
b
=
70
6
a
+
3
b
−
5
=
7
+
3
×
70
6
−
5
=
37
© examsnet.com
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