Home
Class 12
MATHS
The mean and variance of n observations ...

The mean and variance of n observations `x_(1),x_(2),x_(3),...x_(n)` are 5 and 0 respectively.
If `sum_(i=1)^(n)x_(i)^(2)=400` , then the value of n is equal to

A

80

B

25

C

20

D

16

Text Solution

Verified by Experts

Promotional Banner

Topper's Solved these Questions

  • STATISTICS

    NEW JOYTHI PUBLICATION|Exercise EXSERCISE|34 Videos

  • SETS

    NEW JOYTHI PUBLICATION|Exercise QUESTIONS FROM COMPETITIVE EXAMS|21 Videos

  • STRAIGHT LINES

    NEW JOYTHI PUBLICATION|Exercise QUESTIONS FROM COMPETITIVE EXAMS|122 Videos

Similar Questions

Explore conceptually related problems

The standard deviation of n obervations x_(1),x_(2).....,x_(n) is 2. If sum_(i=1)^(n)x_(i)=20andsum_(i=1)^(n)x_(i)^(2)=100 , then n is

Given that bar(x) is the mean and sigma^(2) is the variance of n observation x_(1), x_(2), …x_(n). Prove that the mean and sigma^(2) is the variance of n observations ax_(1),ax_(2), ax_(3),….ax_(n) are abar(x) and a^(2)sigma^(2) , respectively, (ane0) .

A data consists of n observations x_(1), x_(2), ..., x_(n). If Sigma_(i=1)^(n) (x_(i) + 1)^(2) = 9n and Sigma_(i=1)^(n) (x_(i) - 1)^(2) = 5n , then the standard deviation of this data is

Let x_(1),x_(2),…..x_(n) be n observations such that sumx_(i)^(2)=400andsumx_(i)=80 . Then a possible value if n among the following is

If (4x^(2) + 1)^(n) = sum_(r=0)^(n)a_(r)(1+x^(2))^(n-r)x^(2r) , then the value of

Let x_1, x_2 ... x_n be n observations sach that sum x_i^2=200 and sum x_i=40 then least integral value of n

Let (1 + x)^(n) = 1 + a_(1)x + a_(2)x^(2) + ... + a_(n)x^(n) . If a_(1),a_(2) and a_(3) are in A.P., then the value of n is

If each of the observation x_(1), x_(2), ...,x_(n) is increased by 'a', where a is a negative or positive number, show that the variance remains unchanged.

Given (1-x^(3))^(n)=sum_(k=0)^(n)a_(k)x^(k)(1-x)^(3n-2k) then the value of 3*a_(k-1)+a_(k) is

If the constant term in the binomial expansion of (x^2-1/x)^n ,n in N is 15, then the value of n is equal to.

NEW JOYTHI PUBLICATION-STATISTICS-QUESTIONS FROM COMPETITIVE EXAMS
  1. If ""^(n)C(8)=""^(n)C(2), find ""^(n)C(2).

    Text Solution

    |

  2. The arithmetic mean of 7 consecutive integers starting with 'a' is m. ...

    Text Solution

    |

  3. The mean and variance of n observations x(1),x(2),x(3),...x(n) are 5 a...

    Text Solution

    |

  4. If the standard deviation of 3,8,6,10,12,9,11,10,12,7 is 2.71 , then t...

    Text Solution

    |

  5. The A.M of 9 terms is 15. If one more term is added to this series , ...

    Text Solution

    |

  6. If the average of the numbers 1,2,3,…., 98,99,x is 100x, then the valu...

    Text Solution

    |

  7. If the median of (x)/(5),x,(x)/(4),(x)/(2),(x)/(3)(xgt0) is 8, then t...

    Text Solution

    |

  8. The mean of five numbers is 0 and their variance is 2. If three of tho...

    Text Solution

    |

  9. A batsman in his 16^(th) innings makes a score of 70 runs and thereby ...

    Text Solution

    |

  10. If the variance of 1,2,3,4,5,….., x is 10, then the value of x is

    Text Solution

    |

  11. Mean of 10 observations is 50 and their standard deviation is 10 If e...

    Text Solution

    |

  12. If sum(i=1)^(9)(x(i)-5)=9andsum(i=1)^(9)(x(i)-5)^(2)=45, then the sta...

    Text Solution

    |

  13. The standard deviation of 9,16,23,30,37,44,51 is

    Text Solution

    |

  14. In a class of 100 students there are 70 boys whose average marks in a ...

    Text Solution

    |

  15. In an experiment with 15 observation on x, the following results were...

    Text Solution

    |

  16. The median of a set of a set of 9 distinct observations is 20.5 . If e...

    Text Solution

    |

  17. Consider the following statements. (i) Mode can be computed from hi...

    Text Solution

    |

  18. In a series of 2n observations , half of them equal a and remaining ha...

    Text Solution

    |

  19. In a frequency distribution , the mean and median are 21 and 22 respec...

    Text Solution

    |

  20. Let x(1),x(2),…..x(n) be n observations such that sumx(i)^(2)=400andsu...

    Text Solution

    |