Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • Engineering
  • Solve this problem - Statistics and Probability - JEE Main

Let x_{1},x_{2},....,x_{n}\; \; be \; n observations such that \sum x_{1}^{2}=400\; \; and\; \sum x_{i}=80.  Then a possible value of n among the following is

  • Option 1)

    18

  • Option 2)

    15

  • Option 3)

    12

  • Option 4)

    9

 

Answers (1)

best_answer

As we learnt in

Variance -

In case of discrete data 

\dpi{100} \sigma ^{2}= \left ( \frac{\sum x_{i}^{2}}{n} \right )-\left ( \frac{\sum x_{i}}{n} \right )^{2}

-

 

 \sum x_{i}^{2}=400

\sum x_{i}=80

Variance = \frac{400}{n}-\left(\frac{80}{n} \right )^{2}>0

\frac{400}{n}-\frac{80\times 80}{n^{2}}>0

n - 16 > 0

n > 16

Because variance is always positive.

 

 

 


Option 1)

18

Incorrect

Option 2)

15

Incorrect

Option 3)

12

Incorrect

Option 4)

9

Incorrect

Posted by

Plabita

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE

Similar Questions

Trending Articles/News

anam-khan

JEE Main 2025 exam date this month; updates on reduced syllabus, registration, number of attempts
anam-khan

AP BArch Admission 2024: Registration begins today at apsche.ap.gov.in; eligibility criteria

Latest Question