Learn Numerical Ability Statistical, Delhi Police Exam Numerical Ability Statistical Exercise, Free Online Statistical Lessons

Delhi Police Exam Numerical Ability Study Material

Digitization help student to explore and study their academic courses online, as this gives them flexibility and scheduling their learning at their convenience. Kidsfront has prepared unique course material of Numerical Ability Statistical for Delhi Police Exam student. This free online Numerical Ability study material for Delhi Police Exam will help students in learning and doing practice on Statistical topic of Delhi Police Exam Numerical Ability. The study material on Statistical, help Delhi Police Exam Numerical Ability students to learn every aspect of Statistical and prepare themselves for exams by doing online test exercise for Statistical, as their study progresses in class. Kidsfront provide unique pattern of learning Numerical Ability with free online comprehensive study material and loads of Delhi Police Exam Numerical Ability Statistical exercise prepared by the highly professionals team. Students can understand Statistical concept easily and consolidate their learning by doing practice test on Statistical regularly till they excel in Numerical Ability Statistical.

Statistical

The average marks secured by 36 students was 52. but it was discovered that an item 64 was misred as 64.what is the correct mean of mark?

a) 54
b) 53.5
c) 53
d) 52.5

✔Answer

Correct Answer Is : 52.5

Solution Is :

The mean high temperature of the first four days of a week is 25°C whereas the mean of the last four days is 25.5°C. If the mean of the whole week is 25.2°C, then the temperature of the 4th day is

a) 25.2°C
b) 25.5°C
c) 25.6°C
d) 25°C

✔Answer

Correct Answer Is : 25.6°C

Solution Is :

Find the mean of the first 6 prime numbers?

a) 15 / 3
b) 6
c) 41 / 6
d) 12 /4

✔Answer

✔Solution

Correct Answer Is : 41 / 6

Solution Is : The first 6 prime numbers are 2 , 3 , 5 , 7 ,11 , 13 Mean = ( 2 + 3 + 5 + 7 + 11 + 13 ) / 6 = 41 / 6

The mean proportion of 1.21 and 0.09 is

a) 0.33
b) 3.03
c) 3.3
d) 0.033

✔Answer

✔Solution

Correct Answer Is : 0.33

Solution Is : Mean proportion = √ab here, a=121 and b= 0.09 So, Mean proportion = √1210.09 = √121/100 9/100 √1111/1010 * 33/1010 = 11*3/100 = 33/100 = 0.33.

The arithmetic mean (average) of the first 10 whole numbers is

a) 5
b) 4
c) 5.5
d) 4.5

✔Answer

✔Solution

Correct Answer Is : 4.5

Solution Is : (4) Required average =(0+1+2+3+....+9)/10 =(9(9+1))/(210) 4.5

The mean of 9 observations is 16. One more observation is included and the new mean becomes 17. The 10th observation is

a) 9
b) 16
c) 26
d) 30

✔Answer

✔Solution

Correct Answer Is : 26

Solution Is : (3) Tricky Approach Tenth observation =1017-169 =170-144 =26

The average of x numbers is y and average of y numbers is x. Then , the average of all the numbers taken together is

a) (x+y )/ 2xy
b) 2xy / (x+y)
c) (x2 + y2) /(x+y)
d) Xy/(x+y)

✔Answer

✔Solution

Correct Answer Is : 2xy / (x+y)

Solution Is : Average of x nuber is y . Sum of x numbers = x * y = xy Similarly , average of y numbers is x , Sum of y numbers = y * x = xy Sum of total numbers = xy + xy = 2xy Average of totasl numbers = 2xy / (x+y)

The mean value of 20 observation was found to 75, but later on it was detected that 97 was misread as 79. Find the correct mean.

a) 75.7
b) 75.8
c) 75.9
d) 75.6

✔Answer

✔Solution

Correct Answer Is : 75.9

Solution Is :

Given the mean of five numbers is 27. If one of them is excluded , the mean gets reduced by 2. Determine the excluded number.

a) 45
b) 55
c) 25
d) 35

✔Answer

✔Solution

Correct Answer Is : 35

Solution Is : Mean of 5 numbers = 27
Sum of 5 numbers = 27x5 = 135
Now , Mean of 4 numbers after exclusion of a number = 25
Sum of 4 numbers = 25 x 4 = 100
Excluded number = Sum of 5 numbers - sum of 4 numbers
= 135 - 100 = 35

If x is the mean of n observations x1 , x2 , ...... xn , then the mean of x1/a , x2/a , ,,,,, xn/a is

a) X
b) A x
c) X/a
d) X + a

✔Answer

✔Solution

Correct Answer Is : X/a

Solution Is : When each number is divided by`a` then mean is also divided by`a`
New mean = x/a

PREVIOUS NEXT

❏Computer Practice +

❏English Practice +

❏General Knowledge Practice +

❏Logical Reasoning Practice +

❏Quantitative Aptitude Practice +

Delhi Police Exam Numerical Ability Study Material

Statistical

The average marks secured by 36 students was 52. but it was discovered that an item 64 was misred as 64.what is the correct mean of mark?

Correct Answer Is : 52.5

Solution Is :

The mean high temperature of the first four days of a week is 25°C whereas the mean of the last four days is 25.5°C. If the mean of the whole week is 25.2°C, then the temperature of the 4th day is

Correct Answer Is : 25.6°C

Solution Is :

Find the mean of the first 6 prime numbers?

Correct Answer Is : 41 / 6

Solution Is : The first 6 prime numbers are 2 , 3 , 5 , 7 ,11 , 13 Mean = ( 2 + 3 + 5 + 7 + 11 + 13 ) / 6 = 41 / 6

The mean proportion of 1.21 and 0.09 is

Correct Answer Is : 0.33

Solution Is : Mean proportion = √ab here, a=121 and b= 0.09 So, Mean proportion = √121*0.09 = √121/100 * 9/100 √11*11/10*10 * 3*3/10*10 = 11*3/100 = 33/100 = 0.33.

The arithmetic mean (average) of the first 10 whole numbers is

Correct Answer Is : 4.5

Solution Is : (4) Required average =(0+1+2+3+....+9)/10 =(9*(9+1))/(2*10) 4.5

The mean of 9 observations is 16. One more observation is included and the new mean becomes 17. The 10th observation is

Correct Answer Is : 26

Solution Is : (3) Tricky Approach Tenth observation =10*17-16*9 =170-144 =26

The average of x numbers is y and average of y numbers is x. Then , the average of all the numbers taken together is

Correct Answer Is : 2xy / (x+y)

Solution Is : Average of x nuber is y . Sum of x numbers = x * y = xy Similarly , average of y numbers is x , Sum of y numbers = y * x = xy Sum of total numbers = xy + xy = 2xy Average of totasl numbers = 2xy / (x+y)

The mean value of 20 observation was found to 75, but later on it was detected that 97 was misread as 79. Find the correct mean.

Correct Answer Is : 75.9

Solution Is :

Given the mean of five numbers is 27. If one of them is excluded , the mean gets reduced by 2. Determine the excluded number.

Correct Answer Is : 35

Solution Is : Mean of 5 numbers = 27 Sum of 5 numbers = 27x5 = 135 Now , Mean of 4 numbers after exclusion of a number = 25 Sum of 4 numbers = 25 x 4 = 100 Excluded number = Sum of 5 numbers - sum of 4 numbers = 135 - 100 = 35

If x is the mean of n observations x1 , x2 , ...... xn , then the mean of x1/a , x2/a , ,,,,, xn/a is

Correct Answer Is : X/a

Solution Is : When each number is divided by`a` then mean is also divided by`a` New mean = x/a

Kids Learning

Academics

Competitive Exams

Govt. Jobs Exams

Solution Is : Mean proportion = √ab here, a=121 and b= 0.09 So, Mean proportion = √1210.09 = √121/100 9/100 √1111/1010 * 33/1010 = 11*3/100 = 33/100 = 0.33.

Solution Is : (4) Required average =(0+1+2+3+....+9)/10 =(9(9+1))/(210) 4.5

Solution Is : (3) Tricky Approach Tenth observation =1017-169 =170-144 =26

Solution Is : Mean of 5 numbers = 27
Sum of 5 numbers = 27x5 = 135
Now , Mean of 4 numbers after exclusion of a number = 25
Sum of 4 numbers = 25 x 4 = 100
Excluded number = Sum of 5 numbers - sum of 4 numbers
= 135 - 100 = 35

Solution Is : When each number is divided by`a` then mean is also divided by`a`
New mean = x/a