Page 1
JEE Main Previous Year Questions
(2025): Statistics
Question1: The variance of the numbers ?? , ???? , ???? , ???? , … , ?????? is ____ .
JEE Main 2025 (Online) 23rd January Evening Shift
Answer: 8788
Solution:
Var( 8,21,34,47, … … ,320)
Var( 0,13,26,39, … … ,312)
13
2
· Var( 0,1,2, … … ,24)
13
2
· Var( 1,2,3, … … ,25)
So, ?? 2
= 13
2
× (
25
2
-1
12
)= 8788
Alternate solution
8 + ( ?? - 1) 13 = 320
13?? = 325
?? = 25
no. of terms = 25
mean =
? x
i
n
=
8+21+?+320
25
=
25
2
( 8+320)
25
variance ?? 2
=
? x
i
2
n
- ( mean )
2
=
8
2
+ 21
2
+ ? + 320
2
13
- ( 164)
2
= 8788
Question2: Marks obtains by all the students of class ???? are presented in a freqency
distribution with classes of equal width. Let the median of this grouped data be 14
with median class interval 12-18 and median class frequency 12. If the number of
students whose marks are less than ???? is ???? , then the total number of students is :
JEE Main 2025 (Online) 23rd January Morning Shift
Options:
A. 52
B. 44
C. 40
D. 48
Answer: B
Page 2
JEE Main Previous Year Questions
(2025): Statistics
Question1: The variance of the numbers ?? , ???? , ???? , ???? , … , ?????? is ____ .
JEE Main 2025 (Online) 23rd January Evening Shift
Answer: 8788
Solution:
Var( 8,21,34,47, … … ,320)
Var( 0,13,26,39, … … ,312)
13
2
· Var( 0,1,2, … … ,24)
13
2
· Var( 1,2,3, … … ,25)
So, ?? 2
= 13
2
× (
25
2
-1
12
)= 8788
Alternate solution
8 + ( ?? - 1) 13 = 320
13?? = 325
?? = 25
no. of terms = 25
mean =
? x
i
n
=
8+21+?+320
25
=
25
2
( 8+320)
25
variance ?? 2
=
? x
i
2
n
- ( mean )
2
=
8
2
+ 21
2
+ ? + 320
2
13
- ( 164)
2
= 8788
Question2: Marks obtains by all the students of class ???? are presented in a freqency
distribution with classes of equal width. Let the median of this grouped data be 14
with median class interval 12-18 and median class frequency 12. If the number of
students whose marks are less than ???? is ???? , then the total number of students is :
JEE Main 2025 (Online) 23rd January Morning Shift
Options:
A. 52
B. 44
C. 40
D. 48
Answer: B
Solution:
The median for grouped data is given by:
Median = ?? + (
?? 2
-????
?? )× h
where
?? is the lower limit (or boundary) of the median class.
???? is the cumulative frequency of all classes preceding the median class.
?? is the frequency of the median class.
h is the class width.
?? is the total number of students.
Given:
Median = 14
Median class interval is 12 - 18, so ?? = 12 and the class width h = 18 - 12 = 6.
Frequency of median class ?? = 12.
Cumulative frequency below the median class = 18 (i.e., ???? = 18 ).
Plugging these into the formula:
14 = 12 + (
?? 2
- 18
12
) × 6
Step 1: Subtract 12 from both sides:
2 = (
?? 2
- 18
12
) × 6
Step 2: Simplify the multiplication factor:
(
6
12
)=
1
2
So the equation becomes:
2 =
1
2
(
?? 2
- 18)
Step 3: Multiply both sides by 2 to remove the fraction:
4 =
?? 2
- 18
Step 4: Solve for
?? 2
:
?? 2
= 4 + 18 = 22
Step 5: Multiply both sides by 2 to find ?? :
?? = 44
Thus, the total number of students is 44 .
Question3: For a statistical data ?? ?? , ?? ?? , … , ?? ????
of ???? values, a student obtained the
mean as 5.5 and ?
?? =?? ????
??? ?? ?? = ?????? . He later found that he had noted two values in the
data incorrectly as 4 and 5 , instead of the correct values 6 and 8 , respectively. The
variance of the corrected data is
JEE Main 2025 (Online) 24th January Morning Shift
Options:
Page 3
JEE Main Previous Year Questions
(2025): Statistics
Question1: The variance of the numbers ?? , ???? , ???? , ???? , … , ?????? is ____ .
JEE Main 2025 (Online) 23rd January Evening Shift
Answer: 8788
Solution:
Var( 8,21,34,47, … … ,320)
Var( 0,13,26,39, … … ,312)
13
2
· Var( 0,1,2, … … ,24)
13
2
· Var( 1,2,3, … … ,25)
So, ?? 2
= 13
2
× (
25
2
-1
12
)= 8788
Alternate solution
8 + ( ?? - 1) 13 = 320
13?? = 325
?? = 25
no. of terms = 25
mean =
? x
i
n
=
8+21+?+320
25
=
25
2
( 8+320)
25
variance ?? 2
=
? x
i
2
n
- ( mean )
2
=
8
2
+ 21
2
+ ? + 320
2
13
- ( 164)
2
= 8788
Question2: Marks obtains by all the students of class ???? are presented in a freqency
distribution with classes of equal width. Let the median of this grouped data be 14
with median class interval 12-18 and median class frequency 12. If the number of
students whose marks are less than ???? is ???? , then the total number of students is :
JEE Main 2025 (Online) 23rd January Morning Shift
Options:
A. 52
B. 44
C. 40
D. 48
Answer: B
Solution:
The median for grouped data is given by:
Median = ?? + (
?? 2
-????
?? )× h
where
?? is the lower limit (or boundary) of the median class.
???? is the cumulative frequency of all classes preceding the median class.
?? is the frequency of the median class.
h is the class width.
?? is the total number of students.
Given:
Median = 14
Median class interval is 12 - 18, so ?? = 12 and the class width h = 18 - 12 = 6.
Frequency of median class ?? = 12.
Cumulative frequency below the median class = 18 (i.e., ???? = 18 ).
Plugging these into the formula:
14 = 12 + (
?? 2
- 18
12
) × 6
Step 1: Subtract 12 from both sides:
2 = (
?? 2
- 18
12
) × 6
Step 2: Simplify the multiplication factor:
(
6
12
)=
1
2
So the equation becomes:
2 =
1
2
(
?? 2
- 18)
Step 3: Multiply both sides by 2 to remove the fraction:
4 =
?? 2
- 18
Step 4: Solve for
?? 2
:
?? 2
= 4 + 18 = 22
Step 5: Multiply both sides by 2 to find ?? :
?? = 44
Thus, the total number of students is 44 .
Question3: For a statistical data ?? ?? , ?? ?? , … , ?? ????
of ???? values, a student obtained the
mean as 5.5 and ?
?? =?? ????
??? ?? ?? = ?????? . He later found that he had noted two values in the
data incorrectly as 4 and 5 , instead of the correct values 6 and 8 , respectively. The
variance of the corrected data is
JEE Main 2025 (Online) 24th January Morning Shift
Options:
A. 5
B. 7
C. 9
D. 4
Answer: B
Solution:
Mean x = 5.5
= ?
i=1
10
?x
i
= 5.5 × 10 = 55
= ?
i=1
10
?x
i
2
= 371
( ? x
i
)
new
= 55 - ( 4 + 5)+ ( 6 + 8)= 60
( ? x
i
)
new
= 371 - ( 4
2
+ 5
2
)+ ( 6
2
+ 8
2
)= 430
Variance ?? 2
=
? x
i
2
10
- (
? x
i
10
)
2
?? 2
=
430
10
- (
60
10
)
2
?? 2
= 43 - 36
?? 2
= 7
Question4: Let ?? ?? , ?? ?? , … , ?? ????
be ten observations such that ?
?? =?? ????
?( ?? ?? - ?? )= ???? ,
?
?? =?? ????
?( ?? ?? - ?? )
?? = ???? , ?? > ?? , and their variance is
?? ?? . If ?? and ?? ?? are respectively the
mean and the variance of ?? ( ?? ?? - ?? )+ ?? ?? , ?? ( ?? ?? - ?? )+ ?? ?? , … , ?? ( ?? ????
- ?? )+ ?? ?? , then
????
?? ?? is equal to :
JEE Main 2025 (Online) 29th January Morning Shift
Options:
A. 100
B. 90
C. 120
D. 110
Answer: A
Solution:
?
i=1
10
?x
i
= 50, ? mean = 5
Variance =
4
5
=
? x
i
2
10
- (
? x
i
10
)
2
4
5
=
? x
i
2
10
- 25
Page 4
JEE Main Previous Year Questions
(2025): Statistics
Question1: The variance of the numbers ?? , ???? , ???? , ???? , … , ?????? is ____ .
JEE Main 2025 (Online) 23rd January Evening Shift
Answer: 8788
Solution:
Var( 8,21,34,47, … … ,320)
Var( 0,13,26,39, … … ,312)
13
2
· Var( 0,1,2, … … ,24)
13
2
· Var( 1,2,3, … … ,25)
So, ?? 2
= 13
2
× (
25
2
-1
12
)= 8788
Alternate solution
8 + ( ?? - 1) 13 = 320
13?? = 325
?? = 25
no. of terms = 25
mean =
? x
i
n
=
8+21+?+320
25
=
25
2
( 8+320)
25
variance ?? 2
=
? x
i
2
n
- ( mean )
2
=
8
2
+ 21
2
+ ? + 320
2
13
- ( 164)
2
= 8788
Question2: Marks obtains by all the students of class ???? are presented in a freqency
distribution with classes of equal width. Let the median of this grouped data be 14
with median class interval 12-18 and median class frequency 12. If the number of
students whose marks are less than ???? is ???? , then the total number of students is :
JEE Main 2025 (Online) 23rd January Morning Shift
Options:
A. 52
B. 44
C. 40
D. 48
Answer: B
Solution:
The median for grouped data is given by:
Median = ?? + (
?? 2
-????
?? )× h
where
?? is the lower limit (or boundary) of the median class.
???? is the cumulative frequency of all classes preceding the median class.
?? is the frequency of the median class.
h is the class width.
?? is the total number of students.
Given:
Median = 14
Median class interval is 12 - 18, so ?? = 12 and the class width h = 18 - 12 = 6.
Frequency of median class ?? = 12.
Cumulative frequency below the median class = 18 (i.e., ???? = 18 ).
Plugging these into the formula:
14 = 12 + (
?? 2
- 18
12
) × 6
Step 1: Subtract 12 from both sides:
2 = (
?? 2
- 18
12
) × 6
Step 2: Simplify the multiplication factor:
(
6
12
)=
1
2
So the equation becomes:
2 =
1
2
(
?? 2
- 18)
Step 3: Multiply both sides by 2 to remove the fraction:
4 =
?? 2
- 18
Step 4: Solve for
?? 2
:
?? 2
= 4 + 18 = 22
Step 5: Multiply both sides by 2 to find ?? :
?? = 44
Thus, the total number of students is 44 .
Question3: For a statistical data ?? ?? , ?? ?? , … , ?? ????
of ???? values, a student obtained the
mean as 5.5 and ?
?? =?? ????
??? ?? ?? = ?????? . He later found that he had noted two values in the
data incorrectly as 4 and 5 , instead of the correct values 6 and 8 , respectively. The
variance of the corrected data is
JEE Main 2025 (Online) 24th January Morning Shift
Options:
A. 5
B. 7
C. 9
D. 4
Answer: B
Solution:
Mean x = 5.5
= ?
i=1
10
?x
i
= 5.5 × 10 = 55
= ?
i=1
10
?x
i
2
= 371
( ? x
i
)
new
= 55 - ( 4 + 5)+ ( 6 + 8)= 60
( ? x
i
)
new
= 371 - ( 4
2
+ 5
2
)+ ( 6
2
+ 8
2
)= 430
Variance ?? 2
=
? x
i
2
10
- (
? x
i
10
)
2
?? 2
=
430
10
- (
60
10
)
2
?? 2
= 43 - 36
?? 2
= 7
Question4: Let ?? ?? , ?? ?? , … , ?? ????
be ten observations such that ?
?? =?? ????
?( ?? ?? - ?? )= ???? ,
?
?? =?? ????
?( ?? ?? - ?? )
?? = ???? , ?? > ?? , and their variance is
?? ?? . If ?? and ?? ?? are respectively the
mean and the variance of ?? ( ?? ?? - ?? )+ ?? ?? , ?? ( ?? ?? - ?? )+ ?? ?? , … , ?? ( ?? ????
- ?? )+ ?? ?? , then
????
?? ?? is equal to :
JEE Main 2025 (Online) 29th January Morning Shift
Options:
A. 100
B. 90
C. 120
D. 110
Answer: A
Solution:
?
i=1
10
?x
i
= 50, ? mean = 5
Variance =
4
5
=
? x
i
2
10
- (
? x
i
10
)
2
4
5
=
? x
i
2
10
- 25
? ? x
i
2
= 258 ( 1)
Now ? ?
10
i=1
( x
i
- ?? )
2
= 98
?
i=1
10
?( x
i
2
- 2?? · x
i
+ ?? 2
)= 98
258 - 2?? ( 50)+ 10?? 2
= 98
( ?? - 8) ( ?? - 2)= 0
?? = or ?? = 2 ( as ?? > 2)
? ?? = 8 ( 2)
Now as per the question
2( x
1
- 1)+ 4?? , 2( x
2
- 1)+ 4?? , … .2( x
10
- 1)+ 4??
can be simplified to
2x
1
+ 30,2x
2
+ 30, … .2x
10
+ 30 using eq. (2)
?? = 2( 5)+ 30 = 40 ( 3)
?? 2
= 2
2
(
4
5
)=
16
5
?
????
?? 2
=
8 × 40
16/5
= 100
Question5: If the mean and the variance of ?? , ?? , ?? , ?? , ?? , ???? , ???? , ???? are 9 and 9.25
respectively, then ?? + ?? + ???? is equal to :
JEE Main 2025 (Online) 2nd April Evening Shift
Options:
A. 103
B. 106
C. 100
D. 105
Answer: A
Solution:
Let's set up two equations from the given mean and variance:
Mean = 9 ? total sum = 8 · 9 = 72
Known values sum to 6 + 4 + 8 + 12 + 10 + 13 = 53, so
?? + ?? = 72 - 53 = 19.
Population variance = 9.25 ?
? ?? ?? 2
8
- 9
2
= 9.25 ? ? ?? ?? 2
= 8( 81 + 9.25)= 722.
Known squares sum to 6
2
+ 4
2
+ 8
2
+ 12
2
+ 10
2
+ 13
2
= 529 , so
?? 2
+ ?? 2
= 722 - 529 = 193 .
Page 5
JEE Main Previous Year Questions
(2025): Statistics
Question1: The variance of the numbers ?? , ???? , ???? , ???? , … , ?????? is ____ .
JEE Main 2025 (Online) 23rd January Evening Shift
Answer: 8788
Solution:
Var( 8,21,34,47, … … ,320)
Var( 0,13,26,39, … … ,312)
13
2
· Var( 0,1,2, … … ,24)
13
2
· Var( 1,2,3, … … ,25)
So, ?? 2
= 13
2
× (
25
2
-1
12
)= 8788
Alternate solution
8 + ( ?? - 1) 13 = 320
13?? = 325
?? = 25
no. of terms = 25
mean =
? x
i
n
=
8+21+?+320
25
=
25
2
( 8+320)
25
variance ?? 2
=
? x
i
2
n
- ( mean )
2
=
8
2
+ 21
2
+ ? + 320
2
13
- ( 164)
2
= 8788
Question2: Marks obtains by all the students of class ???? are presented in a freqency
distribution with classes of equal width. Let the median of this grouped data be 14
with median class interval 12-18 and median class frequency 12. If the number of
students whose marks are less than ???? is ???? , then the total number of students is :
JEE Main 2025 (Online) 23rd January Morning Shift
Options:
A. 52
B. 44
C. 40
D. 48
Answer: B
Solution:
The median for grouped data is given by:
Median = ?? + (
?? 2
-????
?? )× h
where
?? is the lower limit (or boundary) of the median class.
???? is the cumulative frequency of all classes preceding the median class.
?? is the frequency of the median class.
h is the class width.
?? is the total number of students.
Given:
Median = 14
Median class interval is 12 - 18, so ?? = 12 and the class width h = 18 - 12 = 6.
Frequency of median class ?? = 12.
Cumulative frequency below the median class = 18 (i.e., ???? = 18 ).
Plugging these into the formula:
14 = 12 + (
?? 2
- 18
12
) × 6
Step 1: Subtract 12 from both sides:
2 = (
?? 2
- 18
12
) × 6
Step 2: Simplify the multiplication factor:
(
6
12
)=
1
2
So the equation becomes:
2 =
1
2
(
?? 2
- 18)
Step 3: Multiply both sides by 2 to remove the fraction:
4 =
?? 2
- 18
Step 4: Solve for
?? 2
:
?? 2
= 4 + 18 = 22
Step 5: Multiply both sides by 2 to find ?? :
?? = 44
Thus, the total number of students is 44 .
Question3: For a statistical data ?? ?? , ?? ?? , … , ?? ????
of ???? values, a student obtained the
mean as 5.5 and ?
?? =?? ????
??? ?? ?? = ?????? . He later found that he had noted two values in the
data incorrectly as 4 and 5 , instead of the correct values 6 and 8 , respectively. The
variance of the corrected data is
JEE Main 2025 (Online) 24th January Morning Shift
Options:
A. 5
B. 7
C. 9
D. 4
Answer: B
Solution:
Mean x = 5.5
= ?
i=1
10
?x
i
= 5.5 × 10 = 55
= ?
i=1
10
?x
i
2
= 371
( ? x
i
)
new
= 55 - ( 4 + 5)+ ( 6 + 8)= 60
( ? x
i
)
new
= 371 - ( 4
2
+ 5
2
)+ ( 6
2
+ 8
2
)= 430
Variance ?? 2
=
? x
i
2
10
- (
? x
i
10
)
2
?? 2
=
430
10
- (
60
10
)
2
?? 2
= 43 - 36
?? 2
= 7
Question4: Let ?? ?? , ?? ?? , … , ?? ????
be ten observations such that ?
?? =?? ????
?( ?? ?? - ?? )= ???? ,
?
?? =?? ????
?( ?? ?? - ?? )
?? = ???? , ?? > ?? , and their variance is
?? ?? . If ?? and ?? ?? are respectively the
mean and the variance of ?? ( ?? ?? - ?? )+ ?? ?? , ?? ( ?? ?? - ?? )+ ?? ?? , … , ?? ( ?? ????
- ?? )+ ?? ?? , then
????
?? ?? is equal to :
JEE Main 2025 (Online) 29th January Morning Shift
Options:
A. 100
B. 90
C. 120
D. 110
Answer: A
Solution:
?
i=1
10
?x
i
= 50, ? mean = 5
Variance =
4
5
=
? x
i
2
10
- (
? x
i
10
)
2
4
5
=
? x
i
2
10
- 25
? ? x
i
2
= 258 ( 1)
Now ? ?
10
i=1
( x
i
- ?? )
2
= 98
?
i=1
10
?( x
i
2
- 2?? · x
i
+ ?? 2
)= 98
258 - 2?? ( 50)+ 10?? 2
= 98
( ?? - 8) ( ?? - 2)= 0
?? = or ?? = 2 ( as ?? > 2)
? ?? = 8 ( 2)
Now as per the question
2( x
1
- 1)+ 4?? , 2( x
2
- 1)+ 4?? , … .2( x
10
- 1)+ 4??
can be simplified to
2x
1
+ 30,2x
2
+ 30, … .2x
10
+ 30 using eq. (2)
?? = 2( 5)+ 30 = 40 ( 3)
?? 2
= 2
2
(
4
5
)=
16
5
?
????
?? 2
=
8 × 40
16/5
= 100
Question5: If the mean and the variance of ?? , ?? , ?? , ?? , ?? , ???? , ???? , ???? are 9 and 9.25
respectively, then ?? + ?? + ???? is equal to :
JEE Main 2025 (Online) 2nd April Evening Shift
Options:
A. 103
B. 106
C. 100
D. 105
Answer: A
Solution:
Let's set up two equations from the given mean and variance:
Mean = 9 ? total sum = 8 · 9 = 72
Known values sum to 6 + 4 + 8 + 12 + 10 + 13 = 53, so
?? + ?? = 72 - 53 = 19.
Population variance = 9.25 ?
? ?? ?? 2
8
- 9
2
= 9.25 ? ? ?? ?? 2
= 8( 81 + 9.25)= 722.
Known squares sum to 6
2
+ 4
2
+ 8
2
+ 12
2
+ 10
2
+ 13
2
= 529 , so
?? 2
+ ?? 2
= 722 - 529 = 193 .
Now use
( ?? + ?? )
2
= ?? 2
+ 2???? + ?? 2
? 19
2
= 193+ 2????
so
361 = 193+ 2???? ? ???? = 84.
Finally,
?? + ?? + ???? = 19 + 84 = 103.
Answer: 103 (Option A).
Question6: Let the Mean and Variance of five observations
?? ?? = ?? , ?? ?? = ?? , ?? ?? = ?? , ?? ?? = ?? and ?? ?? = ?? , ?? > ?? , be 5 and 10
respectively. Then the Variance of the observations
?? + ?? ?? , ?? = ?? , ?? , … , ?? is
JEE Main 2025 (Online) 3rd April Evening Shift
Options:
A. 17
B. 16
C. 16.4
D. 17.4
Answer: B
Solution:
First, find the values of ?? and ?? using the given conditions:
Mean Condition:
5 =
1 + 3 + ?? + 7 + ?? 5
This implies:
?? + ?? = 14
Variance Condition:
1 + 9 + ?? 2
+ 49 + ?? 2
5
- ( 5)
2
= 10
Simplifying, we get:
?? 2
+ ?? 2
= 116
Using ?? + ?? = 14, we have:
?? = 14 - ??
Substitute ?? into the equation for ?? 2
+ ?? 2
:
?? 2
+ ( 14 - ?? )
2
= 116
Expand and simplify:
?? 2
+ 196 - 28?? + ?? 2
= 116
2?? 2
- 28?? + 80 = 0
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