Examsnet
Unconfined exams practice
Home
Exams
Banking Entrance Exams
CUET Exam Papers
Defence Exams
Engineering Exams
Finance Entrance Exams
GATE Exam Practice
Insurance Exams
International Exams
JEE Exams
LAW Entrance Exams
MBA Entrance Exams
MCA Entrance Exams
Medical Entrance Exams
Other Entrance Exams
Police Exams
Public Service Commission (PSC)
RRB Entrance Exams
SSC Exams
State Govt Exams
Subjectwise Practice
Teacher Exams
SET Exams(State Eligibility Test)
UPSC Entrance Exams
Aptitude
Algebra and Higher Mathematics
Arithmetic
Commercial Mathematics
Data Based Mathematics
Geometry and Mensuration
Number System and Numeracy
Problem Solving
Board Exams
Andhra
Bihar
CBSE
Gujarat
Haryana
ICSE
Jammu and Kashmir
Karnataka
Kerala
Madhya Pradesh
Maharashtra
Odisha
Tamil Nadu
Telangana
Uttar Pradesh
English
Competitive English
Certifications
Technical
Cloud Tech Certifications
Security Tech Certifications
Management
IT Infrastructure
More
About
Careers
Contact Us
Our Apps
Privacy
Test Index
JEE Main 27-Jan-2024 Shift 2 Solved Paper
Show Para
Hide Para
Section:
Mathematics
Share question:
© examsnet.com
Question : 21
Total: 90
The mean and standard deviation of 15 observations were found to be 12 and 3 respectively. On rechecking it was found that an observation was read as 10 in place of 12 . If
µ
and
σ
2
denote the mean and variance of the correct observations respectively, then
15
(
µ
+
µ
2
+
σ
2
)
is equal to___
[27-Jan-2024 Shift 2]
Your Answer:
Validate
Solution:
👈: Video Solution
Let the incorrect mean be
µ
′
and standard deviation be
σ
′
We have
µ
′
=
Σ
x
i
15
=
12
⇒
Σ
x
i
=
180
As per given information correct
Σ
x
i
=
180
−
10
+
12
⇒
µ
(
correct mean
)
=
182
15
Also
σ
′
=
√
Σ
x
i
2
15
−
144
=
3
⇒
Σ
x
i
2
=
2295
Correct
Σ
x
i
2
=
2295
−
100
+
144
=
2339
σ
2
(
correct variance
)
=
2339
15
−
182
×
182
15
×
15
Required value
=
15
(
µ
+
µ
2
+
σ
2
)
=
15
(
182
15
+
182
×
182
15
×
15
+
2339
15
−
182
×
182
15
×
15
)
=
15
(
182
15
+
2339
15
)
=
2521
© examsnet.com
Go to Question:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
Prev Question
Next Question